A vulnerability has been identified in Keycloak that could lead to unauthorized information disclosure. While it requires an already authenticated user, the /admin/serverinfo endpoint can inadvertently provide sensitive environment information.

A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively long expiration time, for example, 24 or 48 hours, the cache can grow indefinitely, leading to an OutOfMemoryError. This issue could result in a denial of service condition, preventing legitimate users from accessing the system.