An Improper Access Control vulnerability exists in the Keycloak Admin REST API, where a user possessing only the create-client permission—considered low-privilege by design—can unexpectedly access the /admin/realms/master/users/profile endpoint. This endpoint returns internal user profile schema data, including attribute names, validation rules, display metadata, and permission mappings. Although the attacker cannot view actual user accounts, the exposure of backend schema and rules results from insufficient authorization checks specifically on this endpoint. An authenticated but minimally privileged user can remotely retrieve sensitive configuration metadata, which may be leveraged to craft targeted attacks or prepare future privilege-escalation attempts.