Improper access control vulnerability in the JWT authorization grant preview feature of Keycloak. The issue occurs when the --features jwt-authorization-grant option is enabled, and a user account is disabled. Keycloak fails to validate the user’s disabled status during JWT authorization grant processing. By presenting a valid assertion token from an external identity provider, an attacker can obtain a JWT for a disabled user and use it to access protected endpoints. This can be exploited remotely with low privileges and no user interaction, resulting in unauthorized access to sensitive resources.