diff --git a/Objective-C/CBLReplicatorConfiguration.m b/Objective-C/CBLReplicatorConfiguration.m
index 2ca221bcb..6b46fffe2 100644
--- a/Objective-C/CBLReplicatorConfiguration.m
+++ b/Objective-C/CBLReplicatorConfiguration.m
@@ -86,7 +86,11 @@ - (void) setAuthenticator: (CBLAuthenticator *)authenticator {
 
 - (void) setPinnedServerCertificate: (SecCertificateRef)pinnedServerCertificate {
     [self checkReadonly];
-    _pinnedServerCertificate = pinnedServerCertificate;
+    if (_pinnedServerCertificate != pinnedServerCertificate) {
+        cfrelease(_pinnedServerCertificate);
+        _pinnedServerCertificate = pinnedServerCertificate;
+        cfretain(_pinnedServerCertificate);
+    }
 }
 
 
@@ -187,4 +191,9 @@ - (NSDictionary*) effectiveOptions {
 }
 
 
+- (void) dealloc {
+    cfrelease(_pinnedServerCertificate);
+}
+
+
 @end