A flaw was found in the X.509 client-certificate authenticator of Keycloak, a solution for identity and access management. The issue occurs when the server is configured to check certificate revocation using CRL Distribution Points or OCSP. An attacker can provide a specially crafted certificate that points to a malicious server, causing Keycloak to make unauthorized outbound requests to internal or external endpoints before the certificate is fully validated. This can lead to a blind server-side request forgery (SSRF) attack.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.