Medium · published September 19, 2026
A flaw was found in the OIDC protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs during the token refresh process when the server restores requested audiences from stored client IDs. Keycloak fails to verify if the target audience client is still enabled before issuing a new access token. This allows an application with an existing refresh token to continue obtaining valid access tokens for a disabled client, potentially bypassing administrative access controls for resource servers that rely on offline JWT validation.