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.

Requirements to exploit

An attacker who has previously compromised a long-lived "Remember Me" session (e.g., stole the identity cookie) can maintain access for the full original remember-me lifetime, even after an administrator has attempted to revoke that extended persistence by disabling the feature globally. No direct user-interaction is required.