Entra ID SAML sign-in rejected with AADSTS500172 (invalid signing material)

Ethan Andrews@eandrews

•updated Jul 7, 2026•11•0•13

Detects Entra ID sign-in failures with error code AADSTS500172, indicating that a federated SAML assertion was rejected due to invalid or stale token-signing material. This may indicate an attempt to use a forged or recovered SAML token (e.g., Golden SAML) where the signing key is no longer valid or recognized.