CVE-2026-54781 — CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced
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 SubjectCon…
Published: 2026-07-08 · CVSS: 7.4 · CVSS 3.1
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 confirmation method assertions to authenticate a subject without proving authority over the assertion. This issue is fixed in versions 1.8.1 and 1.9.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7