Keycloak 26.6.4 is a critical security-focused update that addresses several high-impact vulnerabilities, including JWT authentication bypass and privilege escalation flaws. It also updates the Quarkus runtime to version 3.33.2.1 and resolves minor documentation and build issues.

Critical Security Patch Suite — This release addresses eight critical security vulnerabilities including authentication bypass (JWT confusion), privilege escalation (group-admin to realm-admin), and unauthorized resource access via UMA. Failing to upgrade leaves your IAM infrastructure vulnerable to complete administrative takeover and data breaches.