A flaw was found in Keycloak. When deployed in stateless mode with MySQL or MariaDB, a mismatch in row-count semantics between the database driver and Keycloak's application logic allows an attacker to bypass replay protection. This vulnerability enables an attacker who intercepts single-use security artifacts, such as JWT client assertions, DPoP proofs, or one-time password (TOTP) codes, to replay them. Successful exploitation grants unauthorized access to the token endpoint or login flow.

A flaw was found in Keycloak. An offline session continues to be valid when the offline_access scope is removed from the client. The refresh token is accepted and you can continue to request new tokens for the session. As it can lead to a situation where an administrator removes the scope, and assumes that offline sessions are no longer available, but they are.

A flaw was found in Keycloak. Keycloak does not immediately enforce the disabling of the "Remember Me" realm setting on existing user sessions. Sessions created while "Remember Me" was active retain their extended session lifetime until they expire, overriding the administrator's recent security configuration change. This is a logic flaw in session management increases the potential window for successful session hijacking or unauthorized long-term access persistence. The flaw lies in the session expiration logic relying on the session-local "remember-me" flag without validating the current realm-level configuration.