The Keycloak Admin API (/unmanagedAttributes) endpoint fails to respect the visibility configuration defined in the User Profile settings. This allows an administrator with limited privileges (specifically the view-users role) to retrieve sensitive custom attributes—such as phone numbers or personal addresses—that are explicitly configured to be hidden from both users and administrators in the GUI.

Requirements to exploit

The attacker must have a valid account on the realm. The attacker must have the view-users role (considered an admin privilege). The target realm must use the User Profile feature with custom attributes set to restricted visibility. Component affected: org.keycloak.services.resources.admin