Keycloak Identity Provider Authentication Bypass

Keycloak's SAML identity provider broker fails to enforce client disabled status during IdP-initiated SSO flows, allowing attackers with valid credentials to establish authenticated sessions and access other enabled clients without re-authentication. An authenticated remote attacker can exploit this authentication bypass to gain unauthorized access to protected resources across the Keycloak ecosystem. No patch is currently available.

Keycloak's IdentityBrokerService.performLogin endpoint fails to enforce disabled Identity Provider restrictions, allowing attackers with knowledge of an IdP alias to reuse previous login requests and authenticate through administratively disabled external providers. This authentication bypass affects any Keycloak deployment relying on IdP disablement as an access control mechanism. An attacker can exploit this to gain unauthorized access by circumventing intended administrative restrictions on external authentication sources.