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
///
/// Gets the associated with this claims identity.
///
+ [field: NonSerialized]
public SecurityToken SecurityToken { get; internal set; }
///
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
///
/// Base class for security token.
///
- [Serializable]
public abstract class SecurityToken : ISafeLogSecurityArtifact
{
internal virtual IEnumerable CreateClaims(string issuer)