GHSA-48PQ-2XQ3-C2M4 CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced

Impact The relying application is given a ClaimsPrincipal for a subject whose authority over the assertion the sender never proved. There are two distinct exploit shapes: - Holder-of-key downgrade. An attacker who obtains a holder-of-key SAML assertion that was issued without KeyInfo issuer bug,...