From 013966c78dbb0f8151336977153748006f7bde50 Mon Sep 17 00:00:00 2001
From: Aleksey Sanin <aleksey@aleksey.com>
Date: Sat, 3 Oct 2026 11:26:11 -0400
Subject: [PATCH 1/4] (xmlsec-mscng, xmlsec-mscrypto) Enforced CRL verification
 against trusted store; improved Windows build

---
 include/xmlsec/mscng/x509.h       |   7 +-
 include/xmlsec/mscrypto/app.h     |   9 +
 include/xmlsec/mscrypto/symbols.h |  16 +-
 include/xmlsec/mscrypto/x509.h    |  27 ++-
 scripts/build_release.sh          |   2 +-
 scripts/build_windows.sh          |   8 +-
 src/mscng/app.c                   |  59 ++++--
 src/mscng/certkeys.c              |  74 ++++---
 src/mscng/certkeys_dsa.c          |   5 +-
 src/mscng/kw_rfc_3394.c           |   6 +-
 src/mscng/x509.c                  |   3 +
 src/mscng/x509vfy.c               | 199 ++++++++++++++++---
 src/mscrypto/certkeys.c           |   5 +-
 src/mscrypto/ciphers.c            |  16 ++
 src/mscrypto/keysstore.c          |  19 +-
 src/mscrypto/kw_rfc_3394.c        |   6 +-
 src/mscrypto/x509.c               |   2 +
 src/mscrypto/x509vfy.c            | 315 ++++++++++++++++++++++++------
 win32/Makefile.msvc               |  25 ++-
 win32/configure.ps1               |   8 +-
 win32/mycfg.bat                   |   6 +-
 21 files changed, 670 insertions(+), 147 deletions(-)

diff --git a/include/xmlsec/mscng/x509.h b/include/xmlsec/mscng/x509.h
index f520867dc..079a7e6c2 100644
--- a/include/xmlsec/mscng/x509.h
+++ b/include/xmlsec/mscng/x509.h
@@ -72,8 +72,11 @@ XMLSEC_CRYPTO_EXPORT int                xmlSecMSCngX509StoreAdoptTrustedStore (x
 XMLSEC_CRYPTO_EXPORT int                xmlSecMSCngX509StoreAdoptUntrustedStore (xmlSecKeyDataStorePtr store,
                                                                                  HCERTSTORE untrustedStore);
 XMLSEC_CRYPTO_EXPORT PCCERT_CONTEXT     xmlSecMSCngX509StoreVerify           (xmlSecKeyDataStorePtr store,
-                                                                              HCERTSTORE certs,
-                                                                              xmlSecKeyInfoCtxPtr keyInfoCtx);
+                                                                               HCERTSTORE certs,
+                                                                               xmlSecKeyInfoCtxPtr keyInfoCtx);
+XMLSEC_CRYPTO_EXPORT int                xmlSecMSCngX509StoreVerifyKey        (xmlSecKeyDataStorePtr store,
+                                                                               xmlSecKeyPtr key,
+                                                                               xmlSecKeyInfoCtxPtr keyInfoCtx);
 
 /******************************************************************************
  *
diff --git a/include/xmlsec/mscrypto/app.h b/include/xmlsec/mscrypto/app.h
index 1d4151976..f3881008b 100644
--- a/include/xmlsec/mscrypto/app.h
+++ b/include/xmlsec/mscrypto/app.h
@@ -35,6 +35,15 @@ extern "C" {
   *****************************************************************************/
 XMLSEC_CRYPTO_EXPORT int        xmlSecMSCryptoAppInit                           (const char* config);
 XMLSEC_CRYPTO_EXPORT int        xmlSecMSCryptoAppShutdown                       (void);
+
+/* This getter returns LPCTSTR (const TCHAR*). The width of TCHAR is fixed at
+ * compile time by the UNICODE/_UNICODE macro: wchar_t (2 bytes) when UNICODE
+ * is defined, char (1 byte) otherwise. The underlying string is allocated by
+ * the library with the library's own TCHAR width, so the consuming application
+ * must be compiled with the same UNICODE/_UNICODE setting as the xmlsec
+ * library. If the character sets mismatch, the returned pointer misinterprets
+ * the string (e.g. a wide string read as a narrow one), which is undefined
+ * behavior. */
 XMLSEC_CRYPTO_EXPORT LPCTSTR    xmlSecMSCryptoAppGetCertStoreName               (void);
 
 /******************************************************************************
diff --git a/include/xmlsec/mscrypto/symbols.h b/include/xmlsec/mscrypto/symbols.h
index a036f3f84..dfbc99eba 100644
--- a/include/xmlsec/mscrypto/symbols.h
+++ b/include/xmlsec/mscrypto/symbols.h
@@ -45,15 +45,19 @@ extern "C" {
 #define xmlSecKeyDataGostR3410_2012_512Id       xmlSecMSCryptoKeyDataGost2012_512Id
 #define xmlSecKeyDataHmacId                     xmlSecMSCryptoKeyDataHmacId
 #define xmlSecKeyDataRsaId                      xmlSecMSCryptoKeyDataRsaId
+#ifndef XMLSEC_NO_X509
 #define xmlSecKeyDataX509Id                     xmlSecMSCryptoKeyDataX509Id
 #define xmlSecKeyDataRawX509CertId              xmlSecMSCryptoKeyDataRawX509CertId
+#endif /* XMLSEC_NO_X509 */
 
 /******************************************************************************
  *
  * Key data store ids
- *
-  *****************************************************************************/
+  *
+   *****************************************************************************/
+#ifndef XMLSEC_NO_X509
 #define xmlSecX509StoreId                       xmlSecMSCryptoX509StoreId
+#endif /* XMLSEC_NO_X509 */
 
 /******************************************************************************
  *
@@ -124,7 +128,7 @@ extern "C" {
  *
  * High-level routines for the xmlsec command-line utility
  *
-  *****************************************************************************/
+ *****************************************************************************/
 #define xmlSecCryptoAppInit                     xmlSecMSCryptoAppInit
 #define xmlSecCryptoAppShutdown                 xmlSecMSCryptoAppShutdown
 #define xmlSecCryptoAppDefaultKeysMngrInit      xmlSecMSCryptoAppDefaultKeysMngrInit
@@ -132,17 +136,23 @@ extern "C" {
 #define xmlSecCryptoAppDefaultKeysMngrVerifyKey xmlSecMSCryptoAppDefaultKeysMngrVerifyKey
 #define xmlSecCryptoAppDefaultKeysMngrLoad      xmlSecMSCryptoAppDefaultKeysMngrLoad
 #define xmlSecCryptoAppDefaultKeysMngrSave      xmlSecMSCryptoAppDefaultKeysMngrSave
+#ifndef XMLSEC_NO_X509
 #define xmlSecCryptoAppKeysMngrCertLoad         xmlSecMSCryptoAppKeysMngrCertLoad
 #define xmlSecCryptoAppKeysMngrCertLoadMemory   xmlSecMSCryptoAppKeysMngrCertLoadMemory
 #define xmlSecCryptoAppKeysMngrCrlLoad          xmlSecMSCryptoAppKeysMngrCrlLoad
 #define xmlSecCryptoAppKeysMngrCrlLoadMemory    xmlSecMSCryptoAppKeysMngrCrlLoadMemory
 #define xmlSecCryptoAppKeysMngrCrlLoadAndVerify xmlSecMSCryptoAppKeysMngrCrlLoadAndVerify
+#endif /* XMLSEC_NO_X509 */
 #define xmlSecCryptoAppKeyLoadEx                xmlSecMSCryptoAppKeyLoadEx
+#ifndef XMLSEC_NO_X509
 #define xmlSecCryptoAppPkcs12Load               xmlSecMSCryptoAppPkcs12Load
 #define xmlSecCryptoAppKeyCertLoad              xmlSecMSCryptoAppKeyCertLoad
+#endif /* XMLSEC_NO_X509 */
 #define xmlSecCryptoAppKeyLoadMemory            xmlSecMSCryptoAppKeyLoadMemory
+#ifndef XMLSEC_NO_X509
 #define xmlSecCryptoAppPkcs12LoadMemory         xmlSecMSCryptoAppPkcs12LoadMemory
 #define xmlSecCryptoAppKeyCertLoadMemory        xmlSecMSCryptoAppKeyCertLoadMemory
+#endif /* XMLSEC_NO_X509 */
 #define xmlSecCryptoAppGetDefaultPwdCallback    xmlSecMSCryptoAppGetDefaultPwdCallback
 
 #endif /* XMLSEC_CRYPTO_MSCRYPTO */
diff --git a/include/xmlsec/mscrypto/x509.h b/include/xmlsec/mscrypto/x509.h
index fbffcd45d..fd5a87d97 100644
--- a/include/xmlsec/mscrypto/x509.h
+++ b/include/xmlsec/mscrypto/x509.h
@@ -79,8 +79,33 @@ XMLSEC_CRYPTO_EXPORT int                xmlSecMSCryptoX509StoreAdoptUntrustedSto
                                                                                  HCERTSTORE untrustedStore);
 
 XMLSEC_CRYPTO_EXPORT void               xmlSecMSCryptoX509StoreEnableSystemTrustedCerts(xmlSecKeyDataStorePtr store,
-                                                                                 int val);
+                                                                                  int val);
 
+XMLSEC_CRYPTO_EXPORT PCCERT_CONTEXT     xmlSecMSCryptoX509StoreVerify           (xmlSecKeyDataStorePtr store,
+                                                                                 HCERTSTORE certs,
+                                                                                 xmlSecKeyInfoCtxPtr keyInfoCtx);
+
+/******************************************************************************
+ *
+ * DEPRECATED
+ *
+  *****************************************************************************/
+XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509StoreFindCert     (xmlSecKeyDataStorePtr store,
+                                                                                           xmlChar *subjectName,
+                                                                                           xmlChar *issuerName,
+                                                                                           xmlChar *issuerSerial,
+                                                                                           xmlChar *ski,
+                                                                                           xmlSecKeyInfoCtxPtr keyInfoCtx);
+XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509StoreFindCert_ex  (xmlSecKeyDataStorePtr store,
+                                                                                           xmlChar* subjectName,
+                                                                                           xmlChar* issuerName,
+                                                                                           xmlChar* issuerSerial,
+                                                                                           xmlSecByte* ski,
+                                                                                           xmlSecSize skiSize,
+                                                                                           xmlSecKeyInfoCtxPtr keyInfoCtx);
+XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509FindCertBySubject (HCERTSTORE store,
+                                                                                            LPCTSTR wcSubject,
+                                                                                            DWORD dwCertEncodingType);
 
 
 #ifdef __cplusplus
diff --git a/scripts/build_release.sh b/scripts/build_release.sh
index 063b52e9f..3bb3cacf9 100755
--- a/scripts/build_release.sh
+++ b/scripts/build_release.sh
@@ -89,7 +89,7 @@ echo "RUN MANUALLY (smtp): cd /home/apps/www/aleksey.com/xmlsec/ && sudo ln -sfn
 
 echo "Verify that the website is working correctly."
 echo "Check the Windows build script, build the Windows version, and upload it to smtp.aleksey.com:"
-echo "RUN MANUALLY (Windows): scp d:\home\aleksey\distro\xmlsec1-${full_version}-win64.zip smtp.aleksey.com:"
+echo "RUN MANUALLY (Windows): scp d:\home\aleksey\distro.release\xmlsec1-${full_version}-win64.zip smtp.aleksey.com:"
 echo "RUN MANUALLY (smtp): sudo cp ~/xmlsec1-${full_version}-win64.zip /home/apps/www/aleksey.com/xmlsec/download/win64/"
 echo "RUN MANUALLY (smtp): cd /home/apps/www/aleksey.com/xmlsec/download/"
 echo "Move old versions to the 'older-releases' folder"
diff --git a/scripts/build_windows.sh b/scripts/build_windows.sh
index fdb5df741..5fffe40cc 100755
--- a/scripts/build_windows.sh
+++ b/scripts/build_windows.sh
@@ -20,7 +20,9 @@ openssl_version="4.0.0"
 xmlsec_version="1.3.13-rc1"
 
 orig_pwd=$(pwd)
-script_dir=$(dirname "$0")
+# "$0" may use Windows backslash separators (e.g. "scripts\build_windows.sh");
+# normalize them to forward slashes so dirname() resolves the script directory.
+script_dir=$(dirname "${0//\\//}")
 
 
 # Build locations, overridable via environment variables.
@@ -219,7 +221,7 @@ function build_openssl {
 
   echo "*** Configuring \"${full_name}\" ..."
   OLD_PATH="$PATH"
-  PATH="$PATH;$PERL_PATH"
+  PATH="${PATH}:${PERL_PATH}"
   cd "${full_name}" || return 1
   perl Configure no-unit-test --prefix="${openssl_install_dir_win}" ${OPENSSL_XMLSEC_CONFIG} VC-WIN64A-HYBRIDCRT
   rc=$?
@@ -303,7 +305,7 @@ function build_xmlsec {
 function create_readme {
   echo "*** Creating README..."
   cd "${orig_pwd}" || return 1
-  cat "${script_dir}\\README-WINDOWS.md.in" | \
+  cat "${script_dir}/README-WINDOWS.md.in" | \
     sed "s/@libxml2_version@/${libxml2_version}/g" | \
     sed "s/@libxslt_version@/${libxslt_version}/g" | \
     sed "s/@openssl_version@/${openssl_version}/g" | \
diff --git a/src/mscng/app.c b/src/mscng/app.c
index a181ad932..943b84dbb 100644
--- a/src/mscng/app.c
+++ b/src/mscng/app.c
@@ -460,9 +460,14 @@ xmlSecMSCngAppKeyLoadMemory(const xmlSecByte* data, xmlSecSize dataSize, xmlSecK
  * @return 0 on success or a negative value otherwise.
  */
 int
-xmlSecMSCngAppKeyCertLoad(xmlSecKeyPtr key, const char* filename,
-                           xmlSecKeyDataFormat format) {
+xmlSecMSCngAppKeyCertLoad(
+    xmlSecKeyPtr key,
+    const char* filename,
+    xmlSecKeyDataFormat format
+) {
     xmlSecBuffer buffer;
+    const xmlSecByte* bufferData;
+    xmlSecSize bufferSize;
     int ret;
 
     xmlSecAssert2(key != NULL, -1);
@@ -483,14 +488,23 @@ xmlSecMSCngAppKeyCertLoad(xmlSecKeyPtr key, const char* filename,
         return(-1);
     }
 
-    ret = xmlSecMSCngAppKeyCertLoadMemory(key, xmlSecBufferGetData(&buffer),
-            xmlSecBufferGetSize(&buffer), format);
+    bufferData = xmlSecBufferGetData(&buffer);
+    bufferSize = xmlSecBufferGetSize(&buffer);
+    if((bufferData == NULL) || (bufferSize == 0)) {
+        xmlSecOtherError2(XMLSEC_ERRORS_R_INVALID_DATA, NULL,
+            "empty file: %s", xmlSecErrorsSafeString(filename));
+        xmlSecBufferFinalize(&buffer);
+        return(-1);
+    }
+
+    ret = xmlSecMSCngAppKeyCertLoadMemory(key, bufferData, bufferSize, format);
     if(ret < 0) {
         xmlSecInternalError("xmlSecMSCngAppKeyCertLoadMemory", NULL);
         xmlSecBufferFinalize(&buffer);
         return(-1);
     }
 
+    /* done */
     xmlSecBufferFinalize(&buffer);
     return(0);
 }
@@ -579,7 +593,7 @@ xmlSecMSCngAppKeyCertLoadMemory(xmlSecKeyPtr key, const xmlSecByte* data, xmlSec
  * in format=xmlSecKeyDataFormatPkcs12.
  *
  * @param filename the PKCS12 key filename.
- * @param pwd the PKCS12 file password.
+ * @param pwd the PKCS12 file password (UTF-8 encoded).
  * @param pwdCallback the password callback. Not supported by the MSCng
  * back-end and ignored; the password must be supplied via @p pwd.
  * @param pwdCallbackCtx the user context for password callback. Not supported
@@ -587,8 +601,10 @@ xmlSecMSCngAppKeyCertLoadMemory(xmlSecKeyPtr key, const xmlSecByte* data, xmlSec
  * @return pointer to the key or NULL if an error occurs.
  */
 xmlSecKeyPtr
-xmlSecMSCngAppPkcs12Load(const char *filename,
-    const char *pwd, void* pwdCallback, void* pwdCallbackCtx
+xmlSecMSCngAppPkcs12Load(
+    const char *filename,
+    const char *pwd,
+    void* pwdCallback, void* pwdCallbackCtx
 ) {
     xmlSecBuffer buffer;
     xmlSecByte* data;
@@ -596,7 +612,11 @@ xmlSecMSCngAppPkcs12Load(const char *filename,
     int ret;
 
     xmlSecAssert2(filename != NULL, NULL);
-    xmlSecAssert2(pwd != NULL, NULL);
+    if(pwd == NULL) {
+        xmlSecOtherError(XMLSEC_ERRORS_R_INVALID_DATA, NULL,
+            "password is required; password callbacks are not supported by the MSCng back-end");
+        return(NULL);
+    }
 
     ret = xmlSecBufferInitialize(&buffer, 0);
     if(ret < 0) {
@@ -668,7 +688,7 @@ xmlSecMSCngIsPrivateKeyCert(PCCERT_CONTEXT cert, BOOL isPersistentKey) {
  *
  * @param data the key binary data.
  * @param dataSize the key binary data size.
- * @param pwd the PKCS12 password.
+ * @param pwd the PKCS12 password (UTF-8 encoded).
  * @param pwdCallback the password callback. Not supported by the MSCng
  * back-end and ignored; the password must be supplied via @p pwd.
  * @param pwdCallbackCtx the user context for password callback. Not supported
@@ -676,9 +696,11 @@ xmlSecMSCngIsPrivateKeyCert(PCCERT_CONTEXT cert, BOOL isPersistentKey) {
  * @return pointer to the key or NULL if an error occurs.
  */
 xmlSecKeyPtr
-xmlSecMSCngAppPkcs12LoadMemory(const xmlSecByte* data, xmlSecSize dataSize, const char *pwd,
-                               void *pwdCallback,
-                               void* pwdCallbackCtx) {
+xmlSecMSCngAppPkcs12LoadMemory(
+    const xmlSecByte* data, xmlSecSize dataSize,
+    const char *pwd,
+    void *pwdCallback, void* pwdCallbackCtx
+) {
     XMLSEC_UNREFERENCED(pwdCallback);
     XMLSEC_UNREFERENCED(pwdCallbackCtx);
     CRYPT_DATA_BLOB pfx;
@@ -694,7 +716,11 @@ xmlSecMSCngAppPkcs12LoadMemory(const xmlSecByte* data, xmlSecSize dataSize, cons
 
     xmlSecAssert2(data != NULL, NULL);
     xmlSecAssert2(dataSize > 0, NULL);
-    xmlSecAssert2(pwd != NULL, NULL);
+    if(pwd == NULL) {
+        xmlSecOtherError(XMLSEC_ERRORS_R_INVALID_DATA, NULL,
+            "password is required; password callbacks are not supported by the MSCng back-end");
+        return(NULL);
+    }
 
     memset(&pfx, 0, sizeof(pfx));
     pfx.pbData = (BYTE *)data;
@@ -706,9 +732,9 @@ xmlSecMSCngAppPkcs12LoadMemory(const xmlSecByte* data, xmlSecSize dataSize, cons
         return(NULL);
     }
 
-    pwdWideChar = xmlSecWin32ConvertLocaleToUnicode(pwd);
+    pwdWideChar = xmlSecWin32ConvertUtf8ToUnicode((const xmlChar*)pwd);
     if(pwdWideChar == NULL) {
-        xmlSecInternalError("xmlSecWin32ConvertLocaleToUnicode", NULL);
+        xmlSecInternalError("xmlSecWin32ConvertUtf8ToUnicode", NULL);
         goto cleanup;
     }
 
@@ -1366,6 +1392,7 @@ xmlSecMSCngAppDefaultKeysMngrSave(xmlSecKeysMngrPtr mngr, const char* filename,
  */
 void*
 xmlSecMSCngAppGetDefaultPwdCallback(void) {
-    /* TODO: MSCNG doesn't support password callback */
+    /* The MSCng backend does not support password callbacks; the password (if any)
+     * must be supplied explicitly via the pwd parameter of the load functions. */
     return(NULL);
 }
diff --git a/src/mscng/certkeys.c b/src/mscng/certkeys.c
index 4d23a3011..46fd0532d 100644
--- a/src/mscng/certkeys.c
+++ b/src/mscng/certkeys.c
@@ -395,7 +395,10 @@ xmlSecMSCngKeyDataGetPubkey(xmlSecKeyDataPtr data) {
  * @param data the key data to retrieve the private key from.
  *
  * @return the private key on success or 0 otherwise. The returned key is
- * owned by the key data; the caller must not destroy it.
+ * owned by the key data; the caller must not destroy it. Note that DH and
+ * X25519 private keys are stored as a BCRYPT_KEY_HANDLE (not an
+ * NCRYPT_KEY_HANDLE) and are not accessible via this function; it returns 0
+ * for such keys.
  */
 NCRYPT_KEY_HANDLE
 xmlSecMSCngKeyDataGetPrivkey(xmlSecKeyDataPtr data) {
@@ -793,9 +796,38 @@ xmlSecMSCngCertKeyDataGetType(xmlSecKeyDataPtr data) {
     return(xmlSecKeyDataTypePublic);
 }
 
+/**
+ * @brief Gets the key strength (in bits) of a CNG public key handle.
+ * @param hKey the CNG public key handle.
+ * @return the key strength in bits, or 0 on failure.
+ */
+static xmlSecSize
+xmlSecMSCngGetPubkeyStrengthInBits(BCRYPT_KEY_HANDLE hKey) {
+    NTSTATUS status;
+    DWORD length = 0;
+    DWORD lenlen = sizeof(length);
+    xmlSecSize res;
+
+    /* Returns the number of bits in the key
+     * https://learn.microsoft.com/en-us/windows/win32/seccng/cng-property-identifiers */
+    status = BCryptGetProperty(hKey,
+        BCRYPT_KEY_STRENGTH,
+        (PUCHAR)&length,
+        lenlen,
+        &lenlen,
+        0);
+    if(status != STATUS_SUCCESS) {
+        xmlSecMSCngNtError("BCryptGetProperty", NULL, status);
+        return(0);
+    }
+    xmlSecAssert2(lenlen == sizeof(length), 0);
+
+    XMLSEC_SAFE_CAST_ULONG_TO_SIZE(length, res, return(0), NULL);
+    return(res);
+}
+
 xmlSecSize
 xmlSecMSCngCertKeyDataGetSizeInBits(xmlSecKeyDataPtr data) {
-    NTSTATUS status;
     xmlSecMSCngKeyDataCtxPtr ctx;
     DWORD length = 0;
     xmlSecSize res;
@@ -812,32 +844,30 @@ xmlSecMSCngCertKeyDataGetSizeInBits(xmlSecKeyDataPtr data) {
          * https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certgetpublickeylength */
         length = CertGetPublicKeyLength(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
             &ctx->cert->pCertInfo->SubjectPublicKeyInfo);
-        if(length == 0) {
-            xmlSecMSCngLastError("CertGetPublicKeyLength", NULL);
-            return(0);
+        if(length != 0) {
+            XMLSEC_SAFE_CAST_ULONG_TO_SIZE(length, res, return(0), NULL);
+            return(res);
         }
-    } else if(ctx->pubkey != 0) {
-        DWORD lenlen = sizeof(length);
-        /* Returns the number of bits in the key
-         * https://learn.microsoft.com/en-us/windows/win32/seccng/cng-property-identifiers */
-        status = BCryptGetProperty(ctx->pubkey,
-            BCRYPT_KEY_STRENGTH,
-            (PUCHAR)&length,
-            lenlen,
-            &lenlen,
-            0);
-        if(status != STATUS_SUCCESS) {
-            xmlSecMSCngNtError("BCryptGetProperty", NULL, status);
-            return(0);
+        /* CertGetPublicKeyLength only understands RSA and some legacy EC/DSA
+         * encodings; it fails for X25519, DH (X9.42) and DSA > 1024.
+         * Fall back to the CNG key strength when the public key handle is available. */
+        if(ctx->pubkey != 0) {
+            return(xmlSecMSCngGetPubkeyStrengthInBits(ctx->pubkey));
         }
-        xmlSecAssert2(lenlen == sizeof(length), 0);
-    } else if(ctx->privkey != 0) {
+        xmlSecMSCngLastError("CertGetPublicKeyLength", NULL);
+        return(0);
+    }
+
+    if(ctx->pubkey != 0) {
+        return(xmlSecMSCngGetPubkeyStrengthInBits(ctx->pubkey));
+    }
+
+    if(ctx->privkey != 0) {
         xmlSecNotImplementedError("MSCNG doesn't support getting key length from private key");
         return(0);
     }
 
-    XMLSEC_SAFE_CAST_ULONG_TO_SIZE(length, res, return(0), NULL);
-    return(res);
+    return(0);
 }
 
 #define XMLSEC_MSCNG_CERTKEY_KLASS_EX(klassName, xmlName, usage, dataNodeName, dataNodeNs, generate, xmlRead, xmlWrite) \
diff --git a/src/mscng/certkeys_dsa.c b/src/mscng/certkeys_dsa.c
index beb0bd089..c3a90855a 100755
--- a/src/mscng/certkeys_dsa.c
+++ b/src/mscng/certkeys_dsa.c
@@ -127,8 +127,8 @@ xmlSecMSCngKeyDataCertGetDsaPubkey(PCERT_PUBLIC_KEY_INFO spki, BCRYPT_KEY_HANDLE
         xmlSecInvalidSizeMoreThanError("DSA Q size", (xmlSecSize)qSize, (xmlSecSize)XMLSEC_MSCNG_DSA_V2_Q_SIZE, NULL);
         goto done;
     }
-    if((gSize > pSize) || (ySize > pSize)) {
-        xmlSecInvalidDataError("invalid DSA key parameters (g/y longer than p)", NULL);
+    if((qSize > pSize) || (gSize > pSize) || (ySize > pSize)) {
+        xmlSecInvalidDataError("invalid DSA key parameters (q/g/y longer than p)", NULL);
         goto done;
     }
 
@@ -452,6 +452,7 @@ xmlSecMSCngKeyDataDsaRead(xmlSecKeyDataId id, xmlSecKeyValueDsaPtr dsaValue) {
         xmlSecInvalidSizeMoreThanError("DSA P size", (xmlSecSize)pSize, (xmlSecSize)XMLSEC_MSCNG_DSA_MAX_P_SIZE, NULL);
         goto done;
     }
+    xmlSecAssert2(qSize <= pSize, NULL);
     xmlSecAssert2(gSize <= pSize, NULL);
     xmlSecAssert2(ySize <= pSize, NULL);
 
diff --git a/src/mscng/kw_rfc_3394.c b/src/mscng/kw_rfc_3394.c
index 928254d4c..239ea8a7e 100644
--- a/src/mscng/kw_rfc_3394.c
+++ b/src/mscng/kw_rfc_3394.c
@@ -389,7 +389,7 @@ xmlSecMSCngKWAesBlockEncrypt(xmlSecTransformPtr transform, const xmlSecByte* in,
     blobSize = xmlSecBufferGetSize(&blob);
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(blobSize, dwBlobSize, goto done, NULL);
 
-    /* perform the actual import */
+    /* perform the key import */
     status = BCryptImportKey(hAlg,
         NULL,
         BCRYPT_KEY_DATA_BLOB,
@@ -404,6 +404,7 @@ xmlSecMSCngKWAesBlockEncrypt(xmlSecTransformPtr transform, const xmlSecByte* in,
         goto done;
     }
 
+    /* perform the encryption */
     cbData = 0;
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(inSize, dwInSize, goto done, NULL);
     status = BCryptEncrypt(hKey,
@@ -539,7 +540,7 @@ xmlSecMSCngKWAesBlockDecrypt(xmlSecTransformPtr transform, const xmlSecByte* in,
     blobSize = xmlSecBufferGetSize(&blob);
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(blobSize, dwBlobSize, goto done, NULL);
 
-    /* perform the actual import */
+    /* perform the key import */
     status = BCryptImportKey(hAlg,
         NULL,
         BCRYPT_KEY_DATA_BLOB,
@@ -554,6 +555,7 @@ xmlSecMSCngKWAesBlockDecrypt(xmlSecTransformPtr transform, const xmlSecByte* in,
         goto done;
     }
 
+    /* perform the decryption */
     cbData = 0;
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(inSize, dwInSize, goto done, NULL);
     status = BCryptDecrypt(hKey,
diff --git a/src/mscng/x509.c b/src/mscng/x509.c
index 9e77568c4..c5c330d90 100644
--- a/src/mscng/x509.c
+++ b/src/mscng/x509.c
@@ -211,11 +211,14 @@ xmlSecMSCngKeyDataX509AdoptKeyCert(xmlSecKeyDataPtr data, PCCERT_CONTEXT cert) {
         CertFreeCertificateContext(cert);  /* caller expects data to own the cert on success. */
         return(0);
     }
+
     /* replace the existing key certificate, duplicate to ensure the private key is copied */
     if(ctx->keyCert != NULL) {
         CertFreeCertificateContext(ctx->keyCert);
         ctx->keyCert = NULL;
     }
+
+    /* replace the existing key certificate, duplicate to ensure the private key is copied */
     ctx->keyCert = CertDuplicateCertificateContext(cert);
     if (ctx->keyCert == NULL) {
         xmlSecMSCngLastError("CertDuplicateCertificateContext", NULL);
diff --git a/src/mscng/x509vfy.c b/src/mscng/x509vfy.c
index e9f07380e..20fd85844 100644
--- a/src/mscng/x509vfy.c
+++ b/src/mscng/x509vfy.c
@@ -56,8 +56,16 @@ XMLSEC_KEY_DATA_STORE_DECLARE(MSCngX509Store, xmlSecMSCngX509StoreCtx)
 #define XMLSEC_CLOSE_STORE_FLAG     (0)
 #endif // _DEBUG
 
-static int              xmlSecMSCngUnixTimeToFileTime            (time_t in,
-                                                                   LPFILETIME out);
+static int              xmlSecMSCngUnixTimeToFileTime               (time_t in,
+                                                                     LPFILETIME out);
+
+static int              xmlSecMSCngX509StoreVerifyCertificateChain  (PCCERT_CONTEXT cert,
+                                                                     FILETIME* time,
+                                                                     HCERTSTORE trustedStore,
+                                                                     HCERTSTORE untrustedStore,
+                                                                     HCERTSTORE certStore,
+                                                                     HCERTSTORE crlStore,
+                                                                     int checkRevocation);
 
 static FILETIME*
 xmlSecMSCngX509StoreGetVerificationTime(xmlSecKeyInfoCtxPtr keyInfoCtx, FILETIME* timeContainer) {
@@ -190,7 +198,7 @@ xmlSecMSCngX509StoreAdoptKeyStore(xmlSecKeyDataStorePtr store, HCERTSTORE keySto
 /**
  * @brief Adds @p trustedStore to the trusted certs list.
  * @details Adds @p trustedStore to the list of trusted certs stores.
-  * @param store the pointer to the X509 key data store instance.
+ * @param store the pointer to the X509 key data store instance.
  * @param trustedStore the pointer to certs store.
  * @return 0 on success or a negative value if an error occurs.
  */
@@ -220,7 +228,7 @@ xmlSecMSCngX509StoreAdoptTrustedStore(xmlSecKeyDataStorePtr store, HCERTSTORE tr
 /**
  * @brief Adds @p untrustedStore to the untrusted certs list.
  * @details Adds @p untrustedStore to the list of untrusted certs stores.
-  * @param store the pointer to the X509 key data store instance.
+ * @param store the pointer to the X509 key data store instance.
  * @param untrustedStore the pointer to certs store.
  * @return 0 on success or a negative value if an error occurs.
  */
@@ -448,15 +456,125 @@ xmlSecMSCngX509StoreAdoptCrl(xmlSecKeyDataStorePtr store, PCCRL_CONTEXT crl) {
     return(0);
 }
 
+/* Returns 1 if the CRL signature verifies against a trusted issuer
+ * certificate, 0 if it does not, or a negative value if an error occurs.
+ * Issuers found outside the trusted store must still chain to trust, but that
+ * chain validation skips revocation to avoid recursively consulting the CRL
+ * being verified. */
+static int
+xmlSecMSCngX509StoreVerifyCrlSignature(
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
+    HCERTSTORE certStore,
+    PCCRL_CONTEXT crl,
+    FILETIME* time
+) {
+    PCCERT_CONTEXT issuerCert = NULL;
+    HCERTSTORE stores[2];
+    int numStores = 0;
+    int ii;
+    BOOL verified = FALSE;
+
+    xmlSecAssert2(trustedStore != NULL, -1);
+    xmlSecAssert2(crl != NULL, -1);
+    xmlSecAssert2(crl->pCrlInfo != NULL, -1);
+
+    /* find the issuer certificate in the trusted store and verify the CRL signature */
+    issuerCert = CertFindCertificateInStore(trustedStore,
+        X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+        0,
+        CERT_FIND_SUBJECT_NAME,
+        &(crl->pCrlInfo->Issuer),
+        NULL);
+    while (issuerCert != NULL) {
+        verified = CryptVerifyCertificateSignatureEx(
+            (HCRYPTPROV_LEGACY)NULL,
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            CRYPT_VERIFY_CERT_SIGN_SUBJECT_CRL, (void*)crl,
+            CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void*)issuerCert,
+            0, NULL);
+        if (verified == TRUE) {
+            CertFreeCertificateContext(issuerCert);
+            return(1);
+        }
+        /* try next matching cert; CertFindCertificateInStore frees issuerCert
+         * (see https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certfindcertificateinstore) */
+        issuerCert = CertFindCertificateInStore(trustedStore,
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            0,
+            CERT_FIND_SUBJECT_NAME,
+            &(crl->pCrlInfo->Issuer),
+            issuerCert);
+    }
+
+    if ((certStore != NULL) && (certStore != trustedStore)) {
+        stores[numStores++] = certStore;
+    }
+    if ((untrustedStore != NULL) && (untrustedStore != trustedStore) && (untrustedStore != certStore)) {
+        stores[numStores++] = untrustedStore;
+    }
+
+    for (ii = 0; ii < numStores; ++ii) {
+        issuerCert = CertFindCertificateInStore(stores[ii],
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            0,
+            CERT_FIND_SUBJECT_NAME,
+            &(crl->pCrlInfo->Issuer),
+            NULL);
+        while (issuerCert != NULL) {
+            verified = CryptVerifyCertificateSignatureEx(
+                (HCRYPTPROV_LEGACY)NULL,
+                X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+                CRYPT_VERIFY_CERT_SIGN_SUBJECT_CRL, (void*)crl,
+                CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void*)issuerCert,
+                0, NULL);
+            if (verified == TRUE) {
+                int ret;
+
+                ret = xmlSecMSCngX509StoreVerifyCertificateChain(
+                    issuerCert, time, trustedStore, untrustedStore, certStore,
+                    NULL, 0); /* do not check for revocation while verifying the CRL to avoid circular dependency */
+                if (ret < 0) {
+                    xmlSecInternalError("xmlSecMSCngX509StoreVerifyCertificateChain", NULL);
+                    CertFreeCertificateContext(issuerCert);
+                    return(-1);
+                }
+                if (ret == 1) {
+                    CertFreeCertificateContext(issuerCert);
+                    return(1);
+                }
+            }
+            issuerCert = CertFindCertificateInStore(stores[ii],
+                X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+                0,
+                CERT_FIND_SUBJECT_NAME,
+                &(crl->pCrlInfo->Issuer),
+                issuerCert);
+        }
+    }
+
+    /* CRL issuer certificate not found or signature does not verify, or the
+     * issuer certificate does not chain to a trusted root. */
+    return(0);
+}
+
 /**
  * @brief Checks if @p cert is in the CRL of @p store.
  * @param store may contain a CRL
+ * @param trustedStore trusted certificates added via xmlSecMSCngX509StoreAdoptCert()
  * @param cert the certificate that is revoked (or not)
  * @param time the time for CRL validity check (can be NULL)
  * @return 1 if the certificate is NOT revoked, 0 if it is revoked, or a negative value if an error occurs.
  */
 static int
-xmlSecMSCngCheckRevocation(HCERTSTORE store, PCCERT_CONTEXT cert, LPFILETIME time) {
+xmlSecMSCngCheckRevocation(
+    HCERTSTORE store,
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
+    HCERTSTORE certStore,
+    PCCERT_CONTEXT cert,
+    LPFILETIME time
+) {
     PCCRL_CONTEXT crlCtx = NULL;
     PCRL_ENTRY crlEntry = NULL;
     int isCrlTimeValid;
@@ -468,12 +586,26 @@ xmlSecMSCngCheckRevocation(HCERTSTORE store, PCCERT_CONTEXT cert, LPFILETIME tim
     /* CertEnumCRLsInStore automatically frees the previous CRL context (see
      * https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certenumcrlsinstore) */
     while((crlCtx = CertEnumCRLsInStore(store, crlCtx)) != NULL) {
+        /* only trust CRLs whose signature verifies against a trusted issuer; a CRL
+         * embedded in the document is controlled by the document author, so an
+         * unverified (forged) CRL must not be able to revoke a certificate */
+        ret = xmlSecMSCngX509StoreVerifyCrlSignature(trustedStore,
+            untrustedStore, certStore, crlCtx, time);
+        if(ret < 0) {
+            xmlSecInternalError("xmlSecMSCngX509StoreVerifyCrlSignature", NULL);
+            CertFreeCRLContext(crlCtx);
+            return(-1);
+        } else if(ret == 0) {
+            continue;
+        }
+
         isCrlTimeValid = xmlSecMSCngX509StoreIsCrlTimeValid(crlCtx, time);
         if(isCrlTimeValid < 0) {
             xmlSecInternalError("xmlSecMSCngX509StoreIsCrlTimeValid", NULL);
             CertFreeCRLContext(crlCtx);
             return(-1);
         } else if(isCrlTimeValid == 0) {
+            /* CRL is not valid at the given time, skip it */
             continue;
         }
 
@@ -490,14 +622,17 @@ xmlSecMSCngCheckRevocation(HCERTSTORE store, PCCERT_CONTEXT cert, LPFILETIME tim
             return(-1);
         }
         if(crlEntry == NULL) {
+            /* Certificate is not listed in the CRL, continue checking other CRLs */
             continue;
         }
 
+        /* Certificate is listed in the CRL, verification failed */
         xmlSecOtherError(XMLSEC_ERRORS_R_CERT_VERIFY_FAILED, NULL, "cert found in CRL");
         CertFreeCRLContext(crlCtx);
         return(0);
     }
 
+    /* No CRL listed the certificate, verification succeeded */
     return(1);
 }
 
@@ -589,13 +724,18 @@ static int
 xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation(
     PCCERT_CONTEXT cert,
     FILETIME* time,
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
     HCERTSTORE certStore,
-    HCERTSTORE crlStore
+    HCERTSTORE crlStore,
+    int checkRevocation
 ) {
     int ret;
 
     xmlSecAssert2(cert != NULL, -1);
     xmlSecAssert2(cert->pCertInfo != NULL, -1);
+    xmlSecAssert2(trustedStore != NULL, -1);
+    xmlSecAssert2(untrustedStore != NULL, -1);
     xmlSecAssert2(certStore != NULL, -1);
 
     /* if time is specified, check certificate notBefore/notAfter */
@@ -611,17 +751,10 @@ xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation(
         }
     }
 
-    /* check certificate revocation */
-    ret = xmlSecMSCngCheckRevocation(certStore, cert, time);
-    if(ret < 0) {
-        xmlSecInternalError("xmlSecMSCngCheckRevocation", NULL);
-        return(-1);
-    } else if (ret != 1) {
-        /* certificate is revoked */
-        return(0);
-    }
-    if(crlStore != NULL) {
-        ret = xmlSecMSCngCheckRevocation(crlStore, cert, time);
+    if(checkRevocation != 0) {
+        /* check certificate revocation */
+        ret = xmlSecMSCngCheckRevocation(certStore, trustedStore,
+            untrustedStore, certStore, cert, time);
         if(ret < 0) {
             xmlSecInternalError("xmlSecMSCngCheckRevocation", NULL);
             return(-1);
@@ -629,6 +762,17 @@ xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation(
             /* certificate is revoked */
             return(0);
         }
+        if(crlStore != NULL) {
+            ret = xmlSecMSCngCheckRevocation(crlStore, trustedStore,
+                untrustedStore, certStore, cert, time);
+            if(ret < 0) {
+                xmlSecInternalError("xmlSecMSCngCheckRevocation", NULL);
+                return(-1);
+            } else if (ret != 1) {
+                /* certificate is revoked */
+                return(0);
+            }
+        }
     }
 
     /* success */
@@ -737,11 +881,19 @@ xmlSecMSCngX509GetCertHash(PCCERT_CONTEXT pCert, BYTE* pHash, DWORD* hashSize) {
  * @param untrustedStore untrusted certificates stack.
  * @param certStore the certificates stack from the document.
  * @param crlStore the CRL store containing certificate revocation lists.
+ * @param checkRevocation if non-zero, perform revocation checks; otherwise
+ * skip revocation and verify only time validity and trust chain.
  * @return 1 on success (cert verified), 0 if cert can't be verified, or a negative value if an error occurs.
  */
 static int
-xmlSecMSCngX509StoreVerifyCertificateChain(PCCERT_CONTEXT cert, FILETIME* time,
-    HCERTSTORE trustedStore, HCERTSTORE untrustedStore, HCERTSTORE certStore, HCERTSTORE crlStore
+xmlSecMSCngX509StoreVerifyCertificateChain(
+    PCCERT_CONTEXT cert,
+    FILETIME* time,
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
+    HCERTSTORE certStore,
+    HCERTSTORE crlStore,
+    int checkRevocation
 ) {
     struct xmlSecMSCngX509StoreVerifyCertificateChainStep * queue = NULL;
     xmlSecSize queueSize = 0, queueMaxSize = 0;
@@ -817,7 +969,8 @@ xmlSecMSCngX509StoreVerifyCertificateChain(PCCERT_CONTEXT cert, FILETIME* time,
         ++seenSize;
 
         /* check certificate itself */
-        ret = xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation(currentCert, time, certStore, crlStore);
+        ret = xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation(currentCert, time,
+            trustedStore, untrustedStore, certStore, crlStore, checkRevocation);
         if(ret < 0) {
             xmlSecInternalError("xmlSecMSCngX509StoreVerifyCertificateValidityAndRevocation", NULL);
             goto done;
@@ -1109,7 +1262,8 @@ xmlSecMSCngX509StoreVerifyCertificate(xmlSecMSCngX509StoreCtxPtr ctx, PCCERT_CON
     }
 
     /* verify based on the own trusted certificates */
-    ret = xmlSecMSCngX509StoreVerifyCertificateChain(cert, time, ctx->trusted, ctx->untrusted, certStore, ctx->crlMemStore);
+    ret = xmlSecMSCngX509StoreVerifyCertificateChain(cert, time, ctx->trusted,
+        ctx->untrusted, certStore, ctx->crlMemStore, 1); /* check for revocation when verifying the certificate */
     if(ret < 0) {
         xmlSecInternalError("xmlSecMSCngX509StoreVerifyCertificateChain", NULL);
         return(-1);
@@ -1279,7 +1433,8 @@ xmlSecMSCngX509StoreVerifyCrl(xmlSecKeyDataStorePtr store, PCCRL_CONTEXT crl,
                     CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void*)issuerCert,
                     0, NULL) == TRUE) {
                 /* verify that the issuer cert itself chains to a trusted root */
-                ret = xmlSecMSCngX509StoreVerifyCertificateChain(issuerCert, time, ctx->trusted, ctx->untrusted, ctx->untrusted, ctx->crlMemStore);
+                ret = xmlSecMSCngX509StoreVerifyCertificateChain(issuerCert,
+                    time, ctx->trusted, ctx->untrusted, ctx->untrusted, NULL, 0); /* do not check for revocation while verifying the issuer cert to avoid circular dependency */
                 if (ret < 0) {
                     xmlSecInternalError("xmlSecMSCngX509StoreVerifyCertificateChain", NULL);
                     CertFreeCertificateContext(issuerCert);
diff --git a/src/mscrypto/certkeys.c b/src/mscrypto/certkeys.c
index 7b1ebf18d..8116ad5d8 100644
--- a/src/mscrypto/certkeys.c
+++ b/src/mscrypto/certkeys.c
@@ -874,8 +874,9 @@ PCCERT_CONTEXT xmlSecMSCryptoCertDup(PCCERT_CONTEXT pCert) {
  * @param pCert the pointer to cert.
  * @param type the expected key type.
  *
- * The function takes ownership of the certificate context; the caller
- * must not free it afterwards.
+ * @details On success, the function takes ownership of the certificate context; the caller
+ * must not free it afterwards. On failure the function does not take ownership and the
+ * caller must free @p pCert.
  *
  * @return pointer to newly created xmlsec key or NULL if an error occurs.
  */
diff --git a/src/mscrypto/ciphers.c b/src/mscrypto/ciphers.c
index 08d694623..8237688ca 100644
--- a/src/mscrypto/ciphers.c
+++ b/src/mscrypto/ciphers.c
@@ -88,6 +88,11 @@ xmlSecMSCryptoBlockCipherCtxInit(xmlSecMSCryptoBlockCipherCtxPtr ctx,
         unsigned char* iv;
 
         /* allocate space for IV */
+        if(outSize > XMLSEC_SIZE_MAX - blockSize) {
+            xmlSecInternalError3("xmlSecBufferSetSize", cipherName,
+                "outSize=" XMLSEC_SIZE_FMT "; blockSize=" XMLSEC_SIZE_FMT, outSize, blockSize);
+            return(-1);
+        }
         ret = xmlSecBufferSetSize(out, outSize + blockSize);
         if(ret < 0) {
             xmlSecInternalError2("xmlSecBufferSetSize", cipherName,
@@ -178,6 +183,12 @@ xmlSecMSCryptoBlockCipherCtxUpdate(xmlSecMSCryptoBlockCipherCtxPtr ctx,
     inSize = inBlocks * blockSize;
 
     /* we write out the input size plus maybe one block */
+    if(outSize > XMLSEC_SIZE_MAX - inSize - blockSize) {
+        xmlSecInternalError4("xmlSecBufferSetMaxSize", cipherName,
+            "outSize=" XMLSEC_SIZE_FMT "; inSize=" XMLSEC_SIZE_FMT "; blockSize=" XMLSEC_SIZE_FMT,
+            outSize, inSize, blockSize);
+        return(-1);
+    }
     ret = xmlSecBufferSetMaxSize(out, outSize + inSize + blockSize);
     if(ret < 0) {
         xmlSecInternalError2("xmlSecBufferSetMaxSize", cipherName,
@@ -292,6 +303,11 @@ xmlSecMSCryptoBlockCipherCtxFinal(xmlSecMSCryptoBlockCipherCtxPtr ctx,
     }
 
     /* process last block */
+    if(outSize > XMLSEC_SIZE_MAX - 2 * blockSize) {
+        xmlSecInternalError3("xmlSecBufferSetMaxSize", cipherName,
+            "outSize=" XMLSEC_SIZE_FMT "; blockSize=" XMLSEC_SIZE_FMT, outSize, blockSize);
+        return(-1);
+    }
     ret = xmlSecBufferSetMaxSize(out, outSize + 2 * blockSize);
     if(ret < 0) {
         xmlSecInternalError2("xmlSecBufferSetMaxSize", cipherName,
diff --git a/src/mscrypto/keysstore.c b/src/mscrypto/keysstore.c
index 848b13a79..7e1072400 100644
--- a/src/mscrypto/keysstore.c
+++ b/src/mscrypto/keysstore.c
@@ -231,7 +231,10 @@ xmlSecMSCryptoKeysStoreFindCert(xmlSecKeyStorePtr store, const xmlChar* name) {
 #endif /* XMLSEC_NO_X509 */
 
     /*
-     * Try to find certificate with name="Friendly Name"
+     * Try to find certificate with name="Friendly Name". This is an O(N)
+     * enumeration over the store: a targeted CertFindCertificateInStore() match
+     * is not possible because CERT_FIND_PROPERTY is an existence check, not a
+     * value match on the friendly-name string.
      */
     if (NULL == pCertContext) {
         DWORD dwPropSize;
@@ -257,6 +260,10 @@ xmlSecMSCryptoKeysStoreFindCert(xmlSecKeyStorePtr store, const xmlChar* name) {
                 break;
             }
 
+            /* CertGetCertificateContextProperty takes a generic LPVOID and has
+             * no _A/_W variant; the friendly-name property (CERT_FRIENDLY_NAME_PROP_ID)
+             * is always a NULL-terminated UTF-16 string, so it can be compared
+             * with lstrcmpW regardless of the library's TCHAR width */
             if (TRUE != CertGetCertificateContextProperty(pCertCtxIter,
                                                       CERT_FRIENDLY_NAME_PROP_ID,
                                                       NULL,
@@ -294,9 +301,8 @@ xmlSecMSCryptoKeysStoreFindCert(xmlSecKeyStorePtr store, const xmlChar* name) {
 
         xmlFree(lpwName);
     }
-
-    /* We don't give up easily, now try to find cert with part of the name
-     */
+    /* We don't give up easily, now try to find cert with part of the name.
+     * This is an indexed lookup. */
     if (NULL == pCertContext) {
         pCertContext = CertFindCertificateInStore(
             hStoreHandle,
@@ -307,7 +313,6 @@ xmlSecMSCryptoKeysStoreFindCert(xmlSecKeyStorePtr store, const xmlChar* name) {
             NULL);
     }
 
-
     /* We could do the following here:
      * It would be nice if we could locate the cert with issuer name and
      * serial number, the given keyname can be something like this:
@@ -450,8 +455,8 @@ xmlSecMSCryptoKeysStoreFindKey(xmlSecKeyStorePtr store, const xmlChar* name,
             goto done;
         }
 
-        /* now that we have a key, make sure it is valid and let the simple
-        * store adopt it */
+        /* now that we have a key, make sure it is valid; the key is returned
+        * to the caller (it is not cached in the simple store) */
         if (xmlSecKeyIsValid(key)) {
             res = key;
             key = NULL;
diff --git a/src/mscrypto/kw_rfc_3394.c b/src/mscrypto/kw_rfc_3394.c
index 6caef4eb3..95b5d96eb 100644
--- a/src/mscrypto/kw_rfc_3394.c
+++ b/src/mscrypto/kw_rfc_3394.c
@@ -298,7 +298,8 @@ xmlSecMSCryptoKWAesBlockEncrypt(xmlSecTransformPtr transform, const xmlSecByte *
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(keySize, dwKeySize, goto done, NULL);
 
     /* Import this key and get an HCRYPTKEY handle. We do it again and again
-       to obtain a fresh session key per call (AES KW runs in ECB mode) */
+     * to obtain a fresh session key per call (AES KW runs in ECB mode).
+     * we do not want to cache the key */
     if (!xmlSecMSCryptoImportPlainSessionBlob(ctx->cryptProvider,
         ctx->pubPrivKey,
         ctx->algorithmIdentifier,
@@ -368,7 +369,8 @@ xmlSecMSCryptoKWAesBlockDecrypt(xmlSecTransformPtr transform, const xmlSecByte *
     XMLSEC_SAFE_CAST_SIZE_TO_ULONG(keySize, dwKeySize, goto done, NULL);
 
     /* Import this key and get an HCRYPTKEY handle. We do it again and again
-       to obtain a fresh session key per call (AES KW runs in ECB mode) */
+     * to obtain a fresh session key per call (AES KW runs in ECB mode).
+     * we do not want to cache the key */
     if (!xmlSecMSCryptoImportPlainSessionBlob(ctx->cryptProvider,
         ctx->pubPrivKey,
         ctx->algorithmIdentifier,
diff --git a/src/mscrypto/x509.c b/src/mscrypto/x509.c
index b6f44b84e..ec9e54125 100644
--- a/src/mscrypto/x509.c
+++ b/src/mscrypto/x509.c
@@ -207,6 +207,8 @@ xmlSecMSCryptoKeyDataX509AdoptKeyCert(xmlSecKeyDataPtr data, PCCERT_CONTEXT cert
     ctx = xmlSecMSCryptoX509DataGetCtx(data);
     xmlSecAssert2(ctx != NULL, -1);
 
+    /* PCERT_CONTEXT is reference-counted, even if this is same cert we need to free the old one
+     * https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certduplicatecertificatecontext */
     if(ctx->keyCert != NULL) {
         CertFreeCertificateContext(ctx->keyCert);
         ctx->keyCert = NULL;
diff --git a/src/mscrypto/x509vfy.c b/src/mscrypto/x509vfy.c
index c7a5ee72b..2336d9b18 100644
--- a/src/mscrypto/x509vfy.c
+++ b/src/mscrypto/x509vfy.c
@@ -61,6 +61,13 @@ XMLSEC_KEY_DATA_STORE_DECLARE(MSCryptoX509Store, xmlSecMSCryptoX509StoreCtx)
 
 static int         xmlSecMSCryptoX509StoreInitialize    (xmlSecKeyDataStorePtr store);
 static void        xmlSecMSCryptoX509StoreFinalize      (xmlSecKeyDataStorePtr store);
+static int         xmlSecMSCryptoBuildCertChain         (PCCERT_CONTEXT cert,
+                                                         LPFILETIME pfTime,
+                                                         HCERTSTORE trustedStore,
+                                                         HCERTSTORE untrustedStore,
+                                                         HCERTSTORE certStore,
+                                                         xmlSecKeyDataStorePtr store,
+                                                         int checkRevocation);
 
 static xmlSecKeyDataStoreKlass xmlSecMSCryptoX509StoreKlass = {
     sizeof(xmlSecKeyDataStoreKlass),
@@ -189,27 +196,160 @@ xmlSecMSCryptoUnixTimeToFileTime(time_t t, LPFILETIME pft) {
     pft->dwHighDateTime = (DWORD)(ll >> 32);
 }
 
+/* Returns TRUE if the CRL is time valid (NotBefore <= time <= NotAfter),
+ * FALSE otherwise. A NULL time skips the check (skip-time-checks flag). */
 static BOOL
-xmlSecMSCryptoVerifyCertTime(PCCERT_CONTEXT pCert, LPFILETIME pft) {
+xmlSecMSCryptoVerifyCertTime(PCCERT_CONTEXT pCert, LPFILETIME pfTime) {
     xmlSecAssert2(pCert != NULL, FALSE);
     xmlSecAssert2(pCert->pCertInfo != NULL, FALSE);
-    xmlSecAssert2(pft != NULL, FALSE);
 
-    if(1 == CompareFileTime(&(pCert->pCertInfo->NotBefore), pft)) {
+    if (pfTime == NULL) {
+        return(TRUE);
+    }
+
+    if(1 == CompareFileTime(&(pCert->pCertInfo->NotBefore), pfTime)) {
         return (FALSE);
     }
-    if(-1 == CompareFileTime(&(pCert->pCertInfo->NotAfter), pft)) {
+    if(-1 == CompareFileTime(&(pCert->pCertInfo->NotAfter), pfTime)) {
         return (FALSE);
     }
 
     return (TRUE);
 }
 
+/* Returns TRUE if the CRL is time valid (thisUpdate <= time <= nextUpdate),
+ * FALSE otherwise. A NULL time skips the check (skip-time-checks flag). */
+static BOOL
+xmlSecMSCryptoVerifyCrlTime(PCCRL_CONTEXT pCrl, LPFILETIME pfTime) {
+    xmlSecAssert2(pCrl != NULL, FALSE);
+    xmlSecAssert2(pCrl->pCrlInfo != NULL, FALSE);
+
+    if (pfTime == NULL) {
+        return(TRUE);
+    }
+
+    if (CompareFileTime(pfTime, &(pCrl->pCrlInfo->ThisUpdate)) < 0) {
+        return(FALSE);
+    }
+
+    if ((pCrl->pCrlInfo->NextUpdate.dwLowDateTime != 0) ||
+            (pCrl->pCrlInfo->NextUpdate.dwHighDateTime != 0)) {
+        if (CompareFileTime(pfTime, &(pCrl->pCrlInfo->NextUpdate)) > 0) {
+            return(FALSE);
+        }
+    }
+
+    return(TRUE);
+}
+
+/* Returns 1 if the CRL signature verifies against a trusted issuer
+ * certificate, 0 if it does not, or a negative value on error. Issuers found
+ * outside the trusted store must still chain to trust, but that chain
+ * validation skips revocation to avoid recursively consulting the CRL being
+ * verified. */
+static int
+xmlSecMSCryptoVerifyCrlSignature(
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
+    HCERTSTORE certStore,
+    PCCRL_CONTEXT pCrl,
+    LPFILETIME pfTime
+) {
+    PCCERT_CONTEXT issuerCert = NULL;
+    HCERTSTORE stores[2];
+    int numStores = 0;
+    int ii;
+
+    xmlSecAssert2(trustedStore != NULL, -1);
+    xmlSecAssert2(pCrl != NULL, -1);
+    xmlSecAssert2(pCrl->pCrlInfo != NULL, -1);
+
+    issuerCert = CertFindCertificateInStore(trustedStore,
+        X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+        0,
+        CERT_FIND_SUBJECT_NAME,
+        &(pCrl->pCrlInfo->Issuer),
+        NULL);
+    while (issuerCert != NULL) {
+        if (CryptVerifyCertificateSignatureEx(
+            (HCRYPTPROV_LEGACY)NULL,
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            CRYPT_VERIFY_CERT_SIGN_SUBJECT_CRL, (void*)pCrl,
+            CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void*)issuerCert,
+            0, NULL) == TRUE) {
+            CertFreeCertificateContext(issuerCert);
+            return(1);
+        }
+
+        /* try next matching cert; CertFindCertificateInStore frees issuerCert
+         * (see https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certfindcertificateinstore) */
+        issuerCert = CertFindCertificateInStore(trustedStore,
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            0,
+            CERT_FIND_SUBJECT_NAME,
+            &(pCrl->pCrlInfo->Issuer),
+            issuerCert);
+    }
+
+    if ((certStore != NULL) && (certStore != trustedStore)) {
+        stores[numStores++] = certStore;
+    }
+    if ((untrustedStore != NULL) && (untrustedStore != trustedStore) && (untrustedStore != certStore)) {
+        stores[numStores++] = untrustedStore;
+    }
+
+    for (ii = 0; ii < numStores; ++ii) {
+        issuerCert = CertFindCertificateInStore(stores[ii],
+            X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+            0,
+            CERT_FIND_SUBJECT_NAME,
+            &(pCrl->pCrlInfo->Issuer),
+            NULL);
+        while (issuerCert != NULL) {
+            if (CryptVerifyCertificateSignatureEx(
+                (HCRYPTPROV_LEGACY)NULL,
+                X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+                CRYPT_VERIFY_CERT_SIGN_SUBJECT_CRL, (void*)pCrl,
+                CRYPT_VERIFY_CERT_SIGN_ISSUER_CERT, (void*)issuerCert,
+                0, NULL) == TRUE) {
+                int ret;
+
+                ret = xmlSecMSCryptoBuildCertChain(
+                    issuerCert, pfTime, trustedStore, untrustedStore, certStore,
+                    NULL, 0); /* do not check for revocation when verifying CRL to avoid infinite recursion */
+                if(ret < 0) {
+                    xmlSecInternalError("xmlSecMSCryptoBuildCertChain", NULL);
+                    CertFreeCertificateContext(issuerCert);
+                    return(-1);
+                }
+                if(ret == 1) {
+                    CertFreeCertificateContext(issuerCert);
+                    return(1);
+                }
+            }
+
+            issuerCert = CertFindCertificateInStore(stores[ii],
+                X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
+                0,
+                CERT_FIND_SUBJECT_NAME,
+                &(pCrl->pCrlInfo->Issuer),
+                issuerCert);
+        }
+    }
+
+    /* no matching issuer found, none of the matching issuers verified the CRL
+     * signature, or the issuer certificate does not chain to a trusted root */
+    return(0);
+}
+
 static BOOL
-xmlSecMSCryptoCheckRevocation(HCERTSTORE hStore, PCCERT_CONTEXT pCert) {
+xmlSecMSCryptoCheckRevocation(HCERTSTORE hStore, PCCERT_CONTEXT pCert,
+    LPFILETIME pfTime, HCERTSTORE trustedStore, HCERTSTORE untrustedStore,
+    HCERTSTORE certStore) {
     PCCRL_CONTEXT pCrl = NULL;
     PCRL_ENTRY pCrlEntry = NULL;
     BOOL ret;
+    int sigRet;
 
     xmlSecAssert2(pCert != NULL, FALSE);
     xmlSecAssert2(hStore != NULL, FALSE);
@@ -217,6 +357,25 @@ xmlSecMSCryptoCheckRevocation(HCERTSTORE hStore, PCCERT_CONTEXT pCert) {
     /* CertEnumCRLsInStore automatically frees the previous CRL context (see
      * https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certenumcrlsinstore) */
     while((pCrl = CertEnumCRLsInStore(hStore, pCrl)) != NULL) {
+        /* check CRL time validity (thisUpdate <= time <= nextUpdate); skip a
+         * CRL that is not yet valid or has expired */
+        if (!xmlSecMSCryptoVerifyCrlTime(pCrl, pfTime)) {
+            continue;
+        }
+
+        /* verify the CRL signature against a trusted issuer; a CRL embedded in
+         * the document is controlled by the document author, so an unverified
+         * (forged) CRL must not be able to revoke a certificate */
+        sigRet = xmlSecMSCryptoVerifyCrlSignature(trustedStore,
+            untrustedStore, certStore, pCrl, pfTime);
+        if (sigRet < 0) {
+            xmlSecInternalError("xmlSecMSCryptoVerifyCrlSignature", NULL);
+            return(FALSE);
+        }
+        if (sigRet == 0) {
+            continue;
+        }
+
         /* pCrlEntry will point to the entry for the certificate in the CRL if it exists, it doesn't need
          * to be freed manually (see https://learn.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-certfindcertificateincrl) */
         ret = CertFindCertificateInCRL(pCert, pCrl, 0, NULL, &pCrlEntry);
@@ -290,7 +449,10 @@ xmlSecBuildChainUsingWinapi (PCCERT_CONTEXT cert, LPFILETIME pfTime,
         xmlSecMSCryptoError("CertGetCertificateChain", NULL);
         goto end;
     }
-    if (pChainContext->TrustStatus.dwErrorStatus == CERT_TRUST_REVOCATION_STATUS_UNKNOWN) {
+    /* retry excluding the root if the revocation status is unknown; the
+     * unknown bit may be combined with other ignorable bits, so use a mask
+     * rather than an exact equality to avoid skipping the retry */
+    if ((pChainContext->TrustStatus.dwErrorStatus & CERT_TRUST_REVOCATION_STATUS_UNKNOWN) != 0) {
         CertFreeCertificateChain(pChainContext); pChainContext = NULL;
         if(!CertGetCertificateChain(NULL,   /* use the default chain engine */
                                     cert,
@@ -451,20 +613,20 @@ xmlSecMSCryptoX509GetCertHash(PCCERT_CONTEXT pCert, BYTE* pHash, DWORD* hashSize
     return(0);
 }
 
-/**
- * @brief Builds certificates chain manually.
- * @param theCert the certificate we check
- * @param pfTime pointer to FILETIME that we are interested in
- * @param store_trusted trusted certificates added via API
- * @param store_untrusted untrusted certificates added via API
- * @param certs untrusted certificates/CRLs extracted from a document
- * @param store pointer to store klass passed to error functions
- * @return TRUE on success or FALSE otherwise.
- */
-static BOOL
-xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
-        HCERTSTORE store_trusted, HCERTSTORE store_untrusted, HCERTSTORE certs,
-        xmlSecKeyDataStorePtr store) {
+/* Returns 1 if @p cert chains to @p trustedStore without using revocation,
+ * 0 if no trusted chain is found, or a negative value on error. This is used
+ * only for CRL issuer certificates to avoid recursively consulting the CRL
+ * currently being verified. */
+static int
+xmlSecMSCryptoBuildCertChain(
+    PCCERT_CONTEXT theCert,
+    LPFILETIME pfTime,
+    HCERTSTORE trustedStore,
+    HCERTSTORE untrustedStore,
+    HCERTSTORE certStore,
+    xmlSecKeyDataStorePtr store,
+    int checkRevocation
+) {
     struct xmlSecMSCryptoBuildCertChainStep * queue = NULL;
     xmlSecSize queueSize = 0, queueMaxSize = 0;
     BYTE seenHashes[XMLSEC_MSCRYPTO_BUILD_CERT_CHAIN_MAX_DEPTH][XMLSEC_MSCRYPTO_X509_CERT_HASH_SIZE];
@@ -473,15 +635,15 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
     DWORD hashSize;
     PCCERT_CONTEXT currentCert = NULL;
     BOOL freeCurrentCert = FALSE;
-    BOOL res = FALSE;
+    const xmlChar* storeName = (store != NULL) ? xmlSecKeyDataStoreGetName(store) : NULL;
+    int res = -1;
     int ret;
 
-    xmlSecAssert2(theCert != NULL, FALSE);
-    xmlSecAssert2(pfTime != NULL, FALSE);
-    xmlSecAssert2(store_trusted != NULL, FALSE);
-    xmlSecAssert2(store_untrusted != NULL, FALSE);
-    xmlSecAssert2(certs != NULL, FALSE);
-    xmlSecAssert2(store != NULL, FALSE);
+    xmlSecAssert2(theCert != NULL, -1);
+    xmlSecAssert2(trustedStore != NULL, -1);
+    xmlSecAssert2(untrustedStore != NULL, -1);
+    xmlSecAssert2(certStore != NULL, -1);
+    xmlSecAssert2((checkRevocation == 0) || (store != NULL), -1);
 
     /* setup queue */
     queue = (struct xmlSecMSCryptoBuildCertChainStep*)xmlMalloc(
@@ -489,7 +651,7 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
     if(queue == NULL) {
         xmlSecMallocError(
             sizeof(struct xmlSecMSCryptoBuildCertChainStep) * XMLSEC_MSCRYPTO_BUILD_CERT_CHAIN_STEP_SIZE, NULL);
-        return(FALSE);
+        return(-1);
     }
     queueMaxSize = XMLSEC_MSCRYPTO_BUILD_CERT_CHAIN_STEP_SIZE;
 
@@ -508,9 +670,9 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
 
         /* limit the chain depth to avoid excessive work on crafted inputs */
         if(seenSize >= XMLSEC_MSCRYPTO_BUILD_CERT_CHAIN_MAX_DEPTH) {
-            xmlSecOtherError(XMLSEC_ERRORS_R_CERT_VERIFY_FAILED,
-                xmlSecKeyDataStoreGetName(store),
+            xmlSecOtherError(XMLSEC_ERRORS_R_CERT_VERIFY_FAILED, storeName,
                 "certificate chain is too deep");
+            res = 0;
             goto done;
         }
 
@@ -544,10 +706,10 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
 
         /* check certificate validity and revocation; an expired/revoked cert
          * cannot be part of a valid chain, so skip this branch (and its issuer)
-         * and continue searching the other branches in the queue */
+         * and continue searching the other branches in the queue. */
         if (!xmlSecMSCryptoVerifyCertTime(currentCert, pfTime)) {
             xmlSecOtherError(XMLSEC_ERRORS_R_CERT_HAS_EXPIRED,
-                xmlSecKeyDataStoreGetName(store),
+                storeName,
                 "certificate expired");
             if(freeCurrentCert == TRUE) {
                 CertFreeCertificateContext(currentCert);
@@ -557,37 +719,40 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
             continue;
         }
 
-        if (!xmlSecMSCryptoCheckRevocation(certs, currentCert)) {
-            xmlSecOtherError(XMLSEC_ERRORS_R_CRL_VERIFY_FAILED,
-                xmlSecKeyDataStoreGetName(store),
-                "certificate revoked");
-            if(freeCurrentCert == TRUE) {
-                CertFreeCertificateContext(currentCert);
+        if(checkRevocation != 0) {
+            if (!xmlSecMSCryptoCheckRevocation(certStore, currentCert, pfTime,
+                    trustedStore, untrustedStore, certStore)) {
+                xmlSecOtherError(XMLSEC_ERRORS_R_CRL_VERIFY_FAILED,
+                    storeName,
+                    "certificate revoked");
+                if(freeCurrentCert == TRUE) {
+                    CertFreeCertificateContext(currentCert);
+                }
+                currentCert = NULL;
+                freeCurrentCert = FALSE;
+                continue;
             }
-            currentCert = NULL;
-            freeCurrentCert = FALSE;
-            continue;
         }
 
         /* does trustedStore contain cert directly? */
-        ret = xmlSecMSCryptoX509StoreContainsCert(store_trusted, &(currentCert->pCertInfo->Subject), currentCert);
+        ret = xmlSecMSCryptoX509StoreContainsCert(trustedStore, &(currentCert->pCertInfo->Subject), currentCert);
         if (ret < 0) {
             xmlSecInternalError("xmlSecMSCryptoX509StoreContainsCert", NULL);
             goto done;
         } else if (ret == 1) {
             /* success */
-            res = TRUE;
+            res = 1;
             goto done;
         }
 
         /* does trustedStore contain the issuer cert? */
-        ret = xmlSecMSCryptoX509StoreContainsCert(store_trusted, &(currentCert->pCertInfo->Issuer), currentCert);
+        ret = xmlSecMSCryptoX509StoreContainsCert(trustedStore, &(currentCert->pCertInfo->Issuer), currentCert);
         if (ret < 0) {
             xmlSecInternalError("xmlSecMSCryptoX509StoreContainsCert", NULL);
             goto done;
         } else if (ret == 1) {
             /* success */
-            res = TRUE;
+            res = 1;
             goto done;
         }
 
@@ -613,7 +778,7 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
             }
 
             /* try the untrusted certs in the chain */
-            issuerCert = xmlSecMSCryptoX509StoreFindIssuer(certs, currentCert);
+            issuerCert = xmlSecMSCryptoX509StoreFindIssuer(certStore, currentCert);
             if(issuerCert != NULL) {
                 xmlSecAssert2(queueSize < queueMaxSize, FALSE);
                 queue[queueSize].cert = issuerCert;
@@ -622,7 +787,7 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
             }
 
             /* try the untrusted certs in the store */
-            issuerCert = xmlSecMSCryptoX509StoreFindIssuer(store_untrusted, currentCert);
+            issuerCert = xmlSecMSCryptoX509StoreFindIssuer(untrustedStore, currentCert);
             if(issuerCert != NULL) {
                 xmlSecAssert2(queueSize < queueMaxSize, FALSE);
                 queue[queueSize].cert = issuerCert;
@@ -638,7 +803,9 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
         freeCurrentCert = FALSE;
     }
 
-    /* not verified */
+    /*  not verified */
+    res = 0;
+
 done:
     if((currentCert != NULL) && (freeCurrentCert == TRUE)) {
         CertFreeCertificateContext(currentCert);
@@ -655,12 +822,37 @@ xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
     return(res);
 }
 
+/**
+ * @brief Builds certificates chain manually.
+ * @param theCert the certificate we check
+ * @param pfTime pointer to FILETIME that we are interested in
+ * @param store_trusted trusted certificates added via API
+ * @param store_untrusted untrusted certificates added via API
+ * @param certs untrusted certificates/CRLs extracted from a document
+ * @param store pointer to store klass passed to error functions
+ * @return TRUE on success or FALSE otherwise.
+ */
+static BOOL
+xmlSecMSCryptoBuildCertChainManually (PCCERT_CONTEXT theCert, LPFILETIME pfTime,
+        HCERTSTORE store_trusted, HCERTSTORE store_untrusted, HCERTSTORE certs,
+        xmlSecKeyDataStorePtr store) {
+    int ret;
+
+    ret = xmlSecMSCryptoBuildCertChain(theCert, pfTime,
+        store_trusted, store_untrusted, certs, store, 1); /* check for revocation when building the certificate chain */
+    if(ret < 0) {
+        return(FALSE);
+    }
+    return((ret == 1) ? TRUE : FALSE);
+}
+
 static BOOL
 xmlSecMSCryptoX509StoreConstructCertsChain(xmlSecKeyDataStorePtr store, PCCERT_CONTEXT cert, HCERTSTORE certs,
                               xmlSecKeyInfoCtx* keyInfoCtx) {
     xmlSecMSCryptoX509StoreCtxPtr ctx;
     PCCERT_CONTEXT tempCert = NULL;
     FILETIME fTime;
+    FILETIME* pfTime;
     BOOL res = FALSE;
 
     xmlSecAssert2(xmlSecKeyDataStoreCheckId(store, xmlSecMSCryptoX509StoreId), FALSE);
@@ -674,14 +866,23 @@ xmlSecMSCryptoX509StoreConstructCertsChain(xmlSecKeyDataStorePtr store, PCCERT_C
     xmlSecAssert2(ctx->trusted != NULL, FALSE);
     xmlSecAssert2(ctx->untrusted != NULL, FALSE);
 
-    if(keyInfoCtx->certsVerificationTime > 0) {
-        /* convert the time to FILETIME */
-        xmlSecMSCryptoUnixTimeToFileTime(keyInfoCtx->certsVerificationTime, &fTime);
+
+
+    /* honor the skip-time-checks flag: pass NULL so the chain builders skip
+     * the certificate notBefore/notAfter checks */
+    if ((keyInfoCtx->flags & XMLSEC_KEYINFO_FLAGS_X509DATA_SKIP_TIME_CHECKS) == 0) {
+        /* get time and convert to FILETIME*/
+        if(keyInfoCtx->certsVerificationTime > 0) {
+            xmlSecMSCryptoUnixTimeToFileTime(keyInfoCtx->certsVerificationTime, &fTime);
+        } else {
+            /* Defaults to current time. GetSystemTimeAsFileTime effectively never
+            * fails, so its return value is not checked.
+            * https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime */
+            GetSystemTimeAsFileTime(&fTime);
+        }
+        pfTime = &fTime;
     } else {
-        /* Defaults to current time. GetSystemTimeAsFileTime effectively never
-         * fails, so its return value is not checked.
-         * https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime */
-        GetSystemTimeAsFileTime(&fTime);
+        pfTime = NULL;
     }
 
     /* try the certificates in the keys manager */
@@ -691,13 +892,13 @@ xmlSecMSCryptoX509StoreConstructCertsChain(xmlSecKeyDataStorePtr store, PCCERT_C
         tempCert = CertEnumCertificatesInStore(ctx->trusted, NULL);
         if(tempCert) {
             CertFreeCertificateContext(tempCert);
-            res = xmlSecMSCryptoBuildCertChainManually(cert, &fTime, ctx->trusted, ctx->untrusted, certs, store);
+            res = xmlSecMSCryptoBuildCertChainManually(cert, pfTime, ctx->trusted, ctx->untrusted, certs, store);
         }
     }
 
     /* try the certificates in the system */
     if(!res && !ctx->dont_use_system_trusted_certs) {
-        res = xmlSecBuildChainUsingWinapi(cert, &fTime, ctx->untrusted, certs);
+        res = xmlSecBuildChainUsingWinapi(cert, pfTime, ctx->untrusted, certs);
     }
 
     /* done */
diff --git a/win32/Makefile.msvc b/win32/Makefile.msvc
index 0a2e8997a..9565d79c3 100644
--- a/win32/Makefile.msvc
+++ b/win32/Makefile.msvc
@@ -64,6 +64,7 @@ AUTOCONF = .\configure.txt
 APP_NAME = xmlseca.exe
 UNIT_TESTS_APP_NAME = xmlsec_unit_testsa.exe
 XMLSEC_FUZZER_APP_NAME = xmlsec_fuzzera.exe
+XMLSEC_RELATIONSHIP_FUZZER_APP_NAME = xmlsec_relationship_fuzzera.exe
 XMLSEC_DSIG_VERIFY_FUZZER_APP_NAME = xmlsec_dsig_verify_fuzzera.exe
 XMLSEC_KEYINFO_FUZZER_APP_NAME = xmlsec_keyinfo_fuzzera.exe
 XMLSEC_KEYLOAD_FUZZER_APP_NAME = xmlsec_keyload_fuzzera.exe
@@ -71,6 +72,7 @@ XMLSEC_KEYLOAD_FUZZER_APP_NAME = xmlsec_keyload_fuzzera.exe
 APP_NAME = xmlsec.exe
 UNIT_TESTS_APP_NAME = xmlsec_unit_tests.exe
 XMLSEC_FUZZER_APP_NAME = xmlsec_fuzzer.exe
+XMLSEC_RELATIONSHIP_FUZZER_APP_NAME = xmlsec_relationship_fuzzer.exe
 XMLSEC_DSIG_VERIFY_FUZZER_APP_NAME = xmlsec_dsig_verify_fuzzer.exe
 XMLSEC_KEYINFO_FUZZER_APP_NAME = xmlsec_keyinfo_fuzzer.exe
 XMLSEC_KEYLOAD_FUZZER_APP_NAME = xmlsec_keyload_fuzzer.exe
@@ -194,6 +196,13 @@ XMLSEC_FUZZER_OBJS_A = \
 	$(XMLSEC_OSS_FUZZ_INTDIR_A)\xmlsec_target.obj \
 	$(XMLSEC_OSS_FUZZ_INTDIR_A)\standalone_fuzz_runner.obj
 
+XMLSEC_RELATIONSHIP_FUZZER_OBJS = \
+	$(XMLSEC_OSS_FUZZ_INTDIR)\xmlsec_relationship_target.obj \
+	$(XMLSEC_OSS_FUZZ_INTDIR)\standalone_fuzz_runner.obj
+XMLSEC_RELATIONSHIP_FUZZER_OBJS_A = \
+	$(XMLSEC_OSS_FUZZ_INTDIR_A)\xmlsec_relationship_target.obj \
+	$(XMLSEC_OSS_FUZZ_INTDIR_A)\standalone_fuzz_runner.obj
+
 XMLSEC_DSIG_VERIFY_FUZZER_OBJS = \
 	$(XMLSEC_OSS_FUZZ_INTDIR)\xmlsec_dsig_verify_target.obj \
 	$(XMLSEC_OSS_FUZZ_INTDIR)\standalone_fuzz_runner.obj
@@ -750,7 +759,7 @@ XMLSEC_OPENSSL_FUZZER_TARGETS =
 XMLSEC_OPENSSL_FUZZER_TARGETS = $(BINDIR)\$(XMLSEC_DSIG_VERIFY_FUZZER_APP_NAME) $(BINDIR)\$(XMLSEC_KEYINFO_FUZZER_APP_NAME) $(BINDIR)\$(XMLSEC_KEYLOAD_FUZZER_APP_NAME)
 !endif
 
-apps: $(BINDIR)\$(APP_NAME) $(BINDIR)\$(UNIT_TESTS_APP_NAME) $(BINDIR)\$(XMLSEC_FUZZER_APP_NAME) $(XMLSEC_OPENSSL_FUZZER_TARGETS)
+apps: $(BINDIR)\$(APP_NAME) $(BINDIR)\$(UNIT_TESTS_APP_NAME) $(BINDIR)\$(XMLSEC_FUZZER_APP_NAME) $(BINDIR)\$(XMLSEC_RELATIONSHIP_FUZZER_APP_NAME) $(XMLSEC_OPENSSL_FUZZER_TARGETS)
 
 xmlseca: $(BINDIR)\$(XMLSEC_A) $(XMLSEC_DEFAULT_CRYPTO_A)
 xmlsec: $(BINDIR)\$(XMLSEC_SO) $(XMLSEC_DEFAULT_CRYPTO)
@@ -769,10 +778,11 @@ mscng: $(BINDIR)\$(XMLSEC_MSCNG_SO)
 
 check : check-unit-tests check-keys check-dsig check-enc check-fuzz
 
-check-fuzz : $(BINDIR)\$(XMLSEC_FUZZER_APP_NAME)
+check-fuzz : $(BINDIR)\$(XMLSEC_FUZZER_APP_NAME) $(BINDIR)\$(XMLSEC_RELATIONSHIP_FUZZER_APP_NAME)
 	set ASAN_OPTIONS=continue_on_error=0
 	cd ..
 	win32\$(BINDIR)\$(XMLSEC_FUZZER_APP_NAME)
+	win32\$(BINDIR)\$(XMLSEC_RELATIONSHIP_FUZZER_APP_NAME)
 	cd win32
 	set ASAN_OPTIONS=
 
@@ -1112,6 +1122,12 @@ $(XMLSEC_FUZZER_RES) : version.rc $(BINDIR)
 		/d "RC_DESCRIPTION=\"XML Security Library - fuzzer\"" \
 		/d "RC_FILETYPE=VFT_APP" /fo $@ version.rc
 
+XMLSEC_RELATIONSHIP_FUZZER_RES = $(BINDIR)\xmlsec-relationship-fuzzer.res
+$(XMLSEC_RELATIONSHIP_FUZZER_RES) : version.rc $(BINDIR)
+	$(RC) $(RCFLAGS) /d "RC_FILENAME=\"$(XMLSEC_RELATIONSHIP_FUZZER_APP_NAME)\"" \
+		/d "RC_DESCRIPTION=\"XML Security Library - OPC relationship fuzzer\"" \
+		/d "RC_FILETYPE=VFT_APP" /fo $@ version.rc
+
 XMLSEC_DSIG_VERIFY_FUZZER_RES = $(BINDIR)\xmlsec-dsig-verify-fuzzer.res
 $(XMLSEC_DSIG_VERIFY_FUZZER_RES) : version.rc $(BINDIR)
 	$(RC) $(RCFLAGS) /d "RC_FILENAME=\"$(XMLSEC_DSIG_VERIFY_FUZZER_APP_NAME)\"" \
@@ -1186,6 +1202,11 @@ $(BINDIR)\xmlsec_fuzzera.exe: xmlseca $(XMLSEC_OSS_FUZZ_INTDIR_A) $(BINDIR) $(XM
 $(BINDIR)\xmlsec_fuzzer.exe: xmlsec $(XMLSEC_OSS_FUZZ_INTDIR) $(BINDIR) $(XMLSEC_FUZZER_OBJS) $(XMLSEC_FUZZER_RES)
 	$(LD) $(LDFLAGS) /OUT:$@ $(XMLSEC_IMP) $(SOLIBS) $(XMLSEC_FUZZER_OBJS) $(XMLSEC_FUZZER_RES)
 
+$(BINDIR)\xmlsec_relationship_fuzzera.exe: xmlseca $(XMLSEC_OSS_FUZZ_INTDIR_A) $(BINDIR) $(XMLSEC_RELATIONSHIP_FUZZER_OBJS_A) $(XMLSEC_RELATIONSHIP_FUZZER_RES)
+	$(LD) $(LDFLAGS) /OUT:$@ $(XMLSEC_A) $(ALIBS) $(XMLSEC_RELATIONSHIP_FUZZER_OBJS_A) $(XMLSEC_RELATIONSHIP_FUZZER_RES)
+$(BINDIR)\xmlsec_relationship_fuzzer.exe: xmlsec $(XMLSEC_OSS_FUZZ_INTDIR) $(BINDIR) $(XMLSEC_RELATIONSHIP_FUZZER_OBJS) $(XMLSEC_RELATIONSHIP_FUZZER_RES)
+	$(LD) $(LDFLAGS) /OUT:$@ $(XMLSEC_IMP) $(SOLIBS) $(XMLSEC_RELATIONSHIP_FUZZER_OBJS) $(XMLSEC_RELATIONSHIP_FUZZER_RES)
+
 $(BINDIR)\xmlsec_dsig_verify_fuzzera.exe: xmlseca $(XMLSEC_OSS_FUZZ_INTDIR_A) $(BINDIR) $(XMLSEC_DSIG_VERIFY_FUZZER_OBJS_A) $(XMLSEC_DSIG_VERIFY_FUZZER_RES)
 	$(LD) $(LDFLAGS) /OUT:$@ $(XMLSEC_A) $(XMLSEC_OPENSSL_A) $(ALIBS) $(XMLSEC_OPENSSL_ALIBS) $(XMLSEC_DSIG_VERIFY_FUZZER_OBJS_A) $(XMLSEC_DSIG_VERIFY_FUZZER_RES)
 $(BINDIR)\xmlsec_dsig_verify_fuzzer.exe: xmlsec $(XMLSEC_OSS_FUZZ_INTDIR) $(BINDIR) $(XMLSEC_DSIG_VERIFY_FUZZER_OBJS) $(XMLSEC_DSIG_VERIFY_FUZZER_RES)
diff --git a/win32/configure.ps1 b/win32/configure.ps1
index 6d324d649..5b6a6ea36 100755
--- a/win32/configure.ps1
+++ b/win32/configure.ps1
@@ -124,6 +124,7 @@ function Show-Usage {
     Write-Host "  hardening:                Build with security hardening flags: /guard:cf, /DYNAMICBASE, and /NXCOMPAT (default: '$(if ($script:buildHardening) { 'yes' } else { 'no' })')"
     Write-Host "  cc:                       Build with the specified compiler (default: '$($script:buildCc)')"
     Write-Host "  cflags:                   Build with the specified compiler flags (default: '$($script:buildCflags)')"
+    Write-Host "  cruntime:                 Compiler runtime library to link (default: '$($script:cruntime)')"
     Write-Host "  static:                   Build static xmlsec libraries (default: '$(if ($script:buildStatic) { 'yes' } else { 'no' })')"
     Write-Host "  apps:                     Build binaries from the 'apps/' folder (default: '$(if ($script:buildApps) { 'yes' } else { 'no' })')"
     Write-Host "  prefix:                   Base directory for the installation (default: '$($script:buildPrefix)')"
@@ -449,7 +450,12 @@ if (-not (Test-Path $makefileMsvc)) {
     Write-Host "ERROR: Cannot find '$makefileMsvc'."
     exit 1
 }
-Copy-Item $makefileMsvc (Join-Path $scriptRoot "Makefile") -Force
+try {
+    Copy-Item $makefileMsvc (Join-Path $scriptRoot "Makefile") -Force -ErrorAction Stop
+} catch {
+    Write-Host "ERROR: Failed to create 'Makefile' from '$makefileMsvc': $($_.Exception.Message)"
+    exit 1
+}
 Write-Host "Created Makefile."
 
 # Display the final configuration.
diff --git a/win32/mycfg.bat b/win32/mycfg.bat
index 98c88b919..966018fc8 100755
--- a/win32/mycfg.bat
+++ b/win32/mycfg.bat
@@ -30,10 +30,12 @@ SET XMLSEC_LIB=%LIBXML2_PREFIX%\lib;%LIBXSLT_PREFIX%\lib;%OPENSSL_PREFIX%\lib
 IF DEFINED MSSDK_LIB SET XMLSEC_LIB=%XMLSEC_LIB%;%MSSDK_LIB%
 SET XMLSEC_OPTIONS=crypto=%XMLSEC_CRYPTO% legacy-features=no static=no pedantic=yes %XMLSEC_OPTIONS%
 
-nmake clean
+REM Makefile is generated by configure.ps1, so on a fresh checkout there is
+REM nothing to clean; only run "nmake clean" when a Makefile is present.
+if exist Makefile nmake clean
 if errorlevel 1 exit /b %ERRORLEVEL%
 del /F /Q Makefile configure.txt
-powershell -ExecutionPolicy Bypass -File configure.ps1 prefix=%XMLSEC_PREFIX% %XMLSEC_OPTIONS% include=%XMLSEC_INCLUDE% lib=%XMLSEC_LIB%
+powershell -ExecutionPolicy Bypass -File configure.ps1 prefix="%XMLSEC_PREFIX%" %XMLSEC_OPTIONS% include="%XMLSEC_INCLUDE%" lib="%XMLSEC_LIB%"
 if errorlevel 1 exit /b %ERRORLEVEL%
 
 @ECHO OFF

From 742721dbe1b92a3a367653a8576f43cda1102776 Mon Sep 17 00:00:00 2001
From: Aleksey Sanin <aleksey@aleksey.com>
Date: Sat, 3 Oct 2026 13:53:00 -0400
Subject: [PATCH 2/4] Fix MinGW and adjust parameters parsing in config script

---
 include/xmlsec/mscng/x509.h | 3 ---
 win32/configure.ps1         | 4 ----
 2 files changed, 7 deletions(-)

diff --git a/include/xmlsec/mscng/x509.h b/include/xmlsec/mscng/x509.h
index 079a7e6c2..7f1cf8d05 100644
--- a/include/xmlsec/mscng/x509.h
+++ b/include/xmlsec/mscng/x509.h
@@ -74,9 +74,6 @@ XMLSEC_CRYPTO_EXPORT int                xmlSecMSCngX509StoreAdoptUntrustedStore
 XMLSEC_CRYPTO_EXPORT PCCERT_CONTEXT     xmlSecMSCngX509StoreVerify           (xmlSecKeyDataStorePtr store,
                                                                                HCERTSTORE certs,
                                                                                xmlSecKeyInfoCtxPtr keyInfoCtx);
-XMLSEC_CRYPTO_EXPORT int                xmlSecMSCngX509StoreVerifyKey        (xmlSecKeyDataStorePtr store,
-                                                                               xmlSecKeyPtr key,
-                                                                               xmlSecKeyInfoCtxPtr keyInfoCtx);
 
 /******************************************************************************
  *
diff --git a/win32/configure.ps1 b/win32/configure.ps1
index 5b6a6ea36..1f9596fd2 100755
--- a/win32/configure.ps1
+++ b/win32/configure.ps1
@@ -303,16 +303,12 @@ $cruntimeSet = 0
 for ($i = 0; ($i -lt $args.Count) -and ($script:errorFlag -eq 0); $i++) {
     $arg = $args[$i]
     $eqIdx = $arg.IndexOf("=")
-    $colIdx = $arg.IndexOf(":")
     $opt = ""
     $sepIdx = -1
 
     if ($eqIdx -ge 0) {
         $opt = $arg.Substring(0, $eqIdx)
         $sepIdx = $eqIdx
-    } elseif ($colIdx -ge 0) {
-        $opt = $arg.Substring(0, $colIdx)
-        $sepIdx = $colIdx
     }
 
     if ($opt.Length -gt 0) {

From be17e633c7be3396a3b14f3b2e9f9f1def1d51eb Mon Sep 17 00:00:00 2001
From: Aleksey Sanin <aleksey@aleksey.com>
Date: Sat, 3 Oct 2026 14:16:20 -0400
Subject: [PATCH 3/4] Fix MinGW

---
 include/xmlsec/mscrypto/x509.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/include/xmlsec/mscrypto/x509.h b/include/xmlsec/mscrypto/x509.h
index fd5a87d97..a2dcab0e4 100644
--- a/include/xmlsec/mscrypto/x509.h
+++ b/include/xmlsec/mscrypto/x509.h
@@ -85,28 +85,6 @@ XMLSEC_CRYPTO_EXPORT PCCERT_CONTEXT     xmlSecMSCryptoX509StoreVerify
                                                                                  HCERTSTORE certs,
                                                                                  xmlSecKeyInfoCtxPtr keyInfoCtx);
 
-/******************************************************************************
- *
- * DEPRECATED
- *
-  *****************************************************************************/
-XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509StoreFindCert     (xmlSecKeyDataStorePtr store,
-                                                                                           xmlChar *subjectName,
-                                                                                           xmlChar *issuerName,
-                                                                                           xmlChar *issuerSerial,
-                                                                                           xmlChar *ski,
-                                                                                           xmlSecKeyInfoCtxPtr keyInfoCtx);
-XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509StoreFindCert_ex  (xmlSecKeyDataStorePtr store,
-                                                                                           xmlChar* subjectName,
-                                                                                           xmlChar* issuerName,
-                                                                                           xmlChar* issuerSerial,
-                                                                                           xmlSecByte* ski,
-                                                                                           xmlSecSize skiSize,
-                                                                                           xmlSecKeyInfoCtxPtr keyInfoCtx);
-XMLSEC_CRYPTO_EXPORT XMLSEC_DEPRECATED PCCERT_CONTEXT xmlSecMSCryptoX509FindCertBySubject (HCERTSTORE store,
-                                                                                            LPCTSTR wcSubject,
-                                                                                            DWORD dwCertEncodingType);
-
 
 #ifdef __cplusplus
 }

From 99c5602a258318b102322c7762065216ec286d78 Mon Sep 17 00:00:00 2001
From: Aleksey Sanin <aleksey@aleksey.com>
Date: Sat, 3 Oct 2026 14:25:21 -0400
Subject: [PATCH 4/4] Fix MinGW

---
 include/xmlsec/mscrypto/x509.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/include/xmlsec/mscrypto/x509.h b/include/xmlsec/mscrypto/x509.h
index a2dcab0e4..99e84a849 100644
--- a/include/xmlsec/mscrypto/x509.h
+++ b/include/xmlsec/mscrypto/x509.h
@@ -81,10 +81,6 @@ XMLSEC_CRYPTO_EXPORT int                xmlSecMSCryptoX509StoreAdoptUntrustedSto
 XMLSEC_CRYPTO_EXPORT void               xmlSecMSCryptoX509StoreEnableSystemTrustedCerts(xmlSecKeyDataStorePtr store,
                                                                                   int val);
 
-XMLSEC_CRYPTO_EXPORT PCCERT_CONTEXT     xmlSecMSCryptoX509StoreVerify           (xmlSecKeyDataStorePtr store,
-                                                                                 HCERTSTORE certs,
-                                                                                 xmlSecKeyInfoCtxPtr keyInfoCtx);
-
 
 #ifdef __cplusplus
 }