CVE-2026-54781

CoreWCF is a port of the service side of Windows Communication Foundation WCF to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML token validation does not enforce SubjectConfirmation method URIs or holder-of-key proof keys in SamlSecurityTokenHandler, allowing holder-of-key downgrade or custom...

GHSA-XJR9-GG9Q-JX3V CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation

Impact Full impersonation of any principal the trusted STS could have issued an assertion for — including administrative principals when the relying party grants them via SAML claims. Affects both SAML 1.1 and SAML 2.0. Preconditions Relying-party service is hosted with WSFederationHttpBinding or...