diff --git a/src/Microsoft.IdentityModel.Tokens/CaseSensitiveClaimsIdentity.cs b/src/Microsoft.IdentityModel.Tokens/CaseSensitiveClaimsIdentity.cs
index a7c85b94ed..19bfb4f099 100644
--- a/src/Microsoft.IdentityModel.Tokens/CaseSensitiveClaimsIdentity.cs
+++ b/src/Microsoft.IdentityModel.Tokens/CaseSensitiveClaimsIdentity.cs
@@ -18,6 +18,7 @@ public class CaseSensitiveClaimsIdentity : ClaimsIdentity
         /// <summary>
         /// Gets the <see cref="SecurityToken"/> associated with this claims identity.
         /// </summary>
+        [field: NonSerialized]
         public SecurityToken SecurityToken { get; internal set; }
 
         /// <summary>
diff --git a/src/Microsoft.IdentityModel.Tokens/SecurityToken.cs b/src/Microsoft.IdentityModel.Tokens/SecurityToken.cs
index afeecf257d..f0e2c7be55 100644
--- a/src/Microsoft.IdentityModel.Tokens/SecurityToken.cs
+++ b/src/Microsoft.IdentityModel.Tokens/SecurityToken.cs
@@ -11,7 +11,6 @@ namespace Microsoft.IdentityModel.Tokens
     /// <summary>
     /// Base class for security token.
     /// </summary>
-    [Serializable]
     public abstract class SecurityToken : ISafeLogSecurityArtifact
     {
         internal virtual IEnumerable<Claim> CreateClaims(string issuer)