diff --git a/internal/rpcserver/rpcserver.go b/internal/rpcserver/rpcserver.go
index c8c8d6762..adb381345 100644
--- a/internal/rpcserver/rpcserver.go
+++ b/internal/rpcserver/rpcserver.go
@@ -5484,10 +5484,9 @@ func (s *Server) checkAuthUserPass(user, pass, remoteAddr string) (bool, bool) {
 // of the server (true) or whether the user is limited (false). The second is
 // always false if the first is.
 func (s *Server) checkAuth(r *http.Request, require bool) (bool, bool, error) {
-	// If admin-level RPC user and pass options are not set, this always
-	// succeeds.  This will be the case when TLS client certificates are
-	// being used for authentication.
-	if s.authsha == ([32]byte{}) {
+	// If no RPC credentials are set this always succeeds. This is the case when
+	// TLS client certificates are being used for authentication.
+	if s.authsha == ([32]byte{}) && s.limitauthsha == ([32]byte{}) {
 		return true, true, nil
 	}
 
@@ -5915,7 +5914,8 @@ func (s *Server) route(ctx context.Context) *http.Server {
 		// Keep track of the number of connected clients.
 		s.incrementClients()
 		defer s.decrementClients()
-		_, isAdmin, err := s.checkAuth(r, true)
+		const required = true
+		_, isAdmin, err := s.checkAuth(r, required)
 		if err != nil {
 			jsonAuthFail(w)
 			return
@@ -5927,7 +5927,8 @@ func (s *Server) route(ctx context.Context) *http.Server {
 
 	// Websocket endpoint.
 	rpcServeMux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
-		authenticated, isAdmin, err := s.checkAuth(r, false)
+		const required = false
+		authenticated, isAdmin, err := s.checkAuth(r, required)
 		if err != nil {
 			jsonAuthFail(w)
 			return
diff --git a/internal/rpcserver/rpcserver_test.go b/internal/rpcserver/rpcserver_test.go
index 038d35e2a..65249e098 100644
--- a/internal/rpcserver/rpcserver_test.go
+++ b/internal/rpcserver/rpcserver_test.go
@@ -1,5 +1,5 @@
 // Copyright (c) 2016 The btcsuite developers
-// Copyright (c) 2017-2022 The Decred developers
+// Copyright (c) 2017-2026 The Decred developers
 
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
@@ -13,7 +13,9 @@ import (
 	"github.com/decred/dcrd/rpc/jsonrpc/types/v4"
 )
 
-func TestCheckAuthUserPass(t *testing.T) {
+// TestAuth_UserPass_AdminAndLimited validates the user/pass authentication when
+// both admin and limited credentials are configured.
+func TestAuth_UserPass_AdminAndLimited(t *testing.T) {
 	s, err := New(&Config{
 		RPCUser:      "user",
 		RPCPass:      "pass",
@@ -67,74 +69,123 @@ func TestCheckAuthUserPass(t *testing.T) {
 		},
 	}
 	for _, test := range tests {
-		authed, isAdmin := s.checkAuthUserPass(test.user, test.pass, "addr")
-		if authed != test.wantAuthed {
-			t.Errorf("%q: unexpected authed -- got %v, want %v", test.name, authed,
-				test.wantAuthed)
+		t.Run(test.name, func(t *testing.T) {
+			authed, isAdmin := s.checkAuthUserPass(test.user, test.pass, "addr")
+			if authed != test.wantAuthed {
+				t.Errorf("unexpected authed -- got %v, want %v", authed,
+					test.wantAuthed)
+			}
+			if isAdmin != test.wantAdmin {
+				t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin,
+					test.wantAdmin)
+			}
+		})
+	}
+}
+
+// TestAuth_Header_NoCredentials validates the header authentication when no
+// credentials are configured.
+func TestAuth_Header_NoCredentials(t *testing.T) {
+	s, err := New(&Config{})
+	if err != nil {
+		t.Fatalf("unable to create RPC server: %v", err)
+	}
+	for _, require := range []bool{true, false} {
+		authed, isAdmin, err := s.checkAuth(&http.Request{}, require)
+		if !authed {
+			t.Errorf("unexpected authed -- got %v, want %v", authed, true)
 		}
-		if isAdmin != test.wantAdmin {
-			t.Errorf("%q: unexpected isAdmin -- got %v, want %v", test.name, isAdmin,
-				test.wantAdmin)
+		if !isAdmin {
+			t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, true)
+		}
+		if err != nil {
+			t.Errorf("unexpected err -- got %v, want %v", err, nil)
 		}
 	}
 }
 
-func TestCheckAuth(t *testing.T) {
-	{
-		s, err := New(&Config{})
-		if err != nil {
-			t.Fatalf("unable to create RPC server: %v", err)
+// TestAuth_Header_LimitedOnly validates the header authentication when only
+// limited credentials are configured.
+func TestAuth_Header_LimitedOnly(t *testing.T) {
+	s, err := New(&Config{
+		RPCLimitUser: "limit",
+		RPCLimitPass: "limit",
+	})
+	if err != nil {
+		t.Fatalf("unable to create RPC server: %v", err)
+	}
+
+	// Reject requests with no auth.
+	authed, isAdmin, err := s.checkAuth(&http.Request{}, true)
+	if authed {
+		t.Errorf("unexpected authed -- got %v, want %v", authed, false)
+	}
+	if isAdmin {
+		t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
+	}
+	if err == nil {
+		t.Errorf("unexpected err -- got %v, want auth failure", err)
+	}
+
+	// Accept request with correct auth, ensure not admin.
+	r := &http.Request{Header: make(map[string][]string, 1)}
+	r.Header["Authorization"] = []string{
+		"Basic bGltaXQ6bGltaXQ=", // limit:limit
+	}
+	authed, isAdmin, err = s.checkAuth(r, true)
+	if !authed {
+		t.Errorf("unexpected authed -- got %v, want %v", authed, true)
+	}
+	if isAdmin {
+		t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
+	}
+	if err != nil {
+		t.Errorf("unexpected err -- got %v, want %v", err, nil)
+	}
+}
+
+// TestAuth_Header_Require validates that setting the require flag causes an
+// error to be returned if the request does not contain an Authorization header.
+func TestAuth_Header_Require(t *testing.T) {
+	s, err := New(&Config{
+		RPCUser:      "user",
+		RPCPass:      "pass",
+		RPCLimitUser: "limit",
+		RPCLimitPass: "limit",
+	})
+	if err != nil {
+		t.Fatalf("unable to create RPC server: %v", err)
+	}
+
+	// Test without Authorization header.
+	for _, require := range []bool{true, false} {
+		authed, isAdmin, err := s.checkAuth(&http.Request{}, require)
+		if authed {
+			t.Errorf("unexpected authed -- got %v, want %v", authed, false)
 		}
-		for i := 0; i <= 1; i++ {
-			authed, isAdmin, err := s.checkAuth(&http.Request{}, i == 0)
-			if !authed {
-				t.Errorf(" unexpected authed -- got %v, want %v", authed, true)
-			}
-			if !isAdmin {
-				t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, true)
-			}
-			if err != nil {
-				t.Errorf("unexpected err -- got %v, want %v", err, nil)
-			}
+		if isAdmin {
+			t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
+		}
+		if require && err == nil {
+			t.Errorf("unexpected err -- got %v, want auth failure", err)
+		} else if !require && err != nil {
+			t.Errorf("unexpected err -- got %v, want <nil>", err)
 		}
 	}
-	{
-		s, err := New(&Config{
-			RPCUser:      "user",
-			RPCPass:      "pass",
-			RPCLimitUser: "limit",
-			RPCLimitPass: "limit",
-		})
-		if err != nil {
-			t.Fatalf("unable to create RPC server: %v", err)
+
+	// Test with Authorization header and invalid credentials.
+	for _, require := range []bool{true, false} {
+		r := &http.Request{Header: make(map[string][]string, 1)}
+		r.Header["Authorization"] = []string{"Basic badcredentials"}
+		authed, isAdmin, err := s.checkAuth(r, require)
+		if authed {
+			t.Errorf("unexpected authed -- got %v, want %v", authed, false)
 		}
-		for i := 0; i <= 1; i++ {
-			authed, isAdmin, err := s.checkAuth(&http.Request{}, i == 0)
-			if authed {
-				t.Errorf(" unexpected authed -- got %v, want %v", authed, false)
-			}
-			if isAdmin {
-				t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
-			}
-			if i == 0 && err == nil {
-				t.Errorf("unexpected err -- got %v, want auth failure", err)
-			} else if i != 0 && err != nil {
-				t.Errorf("unexpected err -- got %v, want <nil>", err)
-			}
+		if isAdmin {
+			t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
 		}
-		for i := 0; i <= 1; i++ {
-			r := &http.Request{Header: make(map[string][]string, 1)}
-			r.Header["Authorization"] = []string{"Basic Nothing"}
-			authed, isAdmin, err := s.checkAuth(r, i == 0)
-			if authed {
-				t.Errorf(" unexpected authed -- got %v, want %v", authed, false)
-			}
-			if isAdmin {
-				t.Errorf("unexpected isAdmin -- got %v, want %v", isAdmin, false)
-			}
-			if err == nil {
-				t.Errorf("unexpected err -- got %v, want auth failure", err)
-			}
+		if err == nil {
+			t.Errorf("unexpected err -- got %v, want auth failure", err)
 		}
 	}
 }