CVE-2025-13881 identifies a privilege assignment flaw in the Red Hat Build of Keycloak's Admin API. Specifically, the vulnerability allows an administrator account with limited privileges—meaning not full superuser rights—to retrieve sensitive custom attributes of users via the /unmanagedAttributes endpoint. This retrieval bypasses the User Profile visibility settings that normally restrict access to such attributes. The vulnerability arises from improper enforcement of privilege checks on this API endpoint, enabling privilege escalation within the administrative domain. The CVSS 3.1 base score is 2.7, reflecting a low severity primarily because the attack vector is network-based, requires high privileges (an admin with limited rights), no user interaction, and impacts confidentiality only to a limited extent. Integrity and availability remain unaffected. No known exploits have been reported, and no patches are currently linked, indicating this is a recently disclosed issue. The flaw could allow unauthorized disclosure of sensitive user data stored as custom attributes, which may include personally identifiable information or other confidential metadata. This vulnerability is relevant for organizations deploying Red Hat's Keycloak for identity and access management, especially where fine-grained user attribute visibility is critical for compliance or privacy.

For European organizations, the primary impact is unauthorized disclosure of sensitive user custom attributes within the administrative context. While the vulnerability does not allow full privilege escalation or system compromise, it undermines the confidentiality of user data managed by Keycloak. This could lead to privacy violations, non-compliance with GDPR if personal data is exposed improperly, and potential insider threat scenarios where administrators with limited rights access more data than intended. Since Keycloak is widely used for authentication and authorization in enterprise and public sector environments across Europe, the exposure of sensitive user metadata could affect identity management integrity and trust. However, the requirement for an admin-level account with limited privileges reduces the risk from external attackers but raises concerns about insider misuse or compromised admin credentials. The lack of impact on integrity and availability means system operations remain stable, but data confidentiality is weakened.

Organizations should immediately audit their Keycloak administrative roles and permissions to ensure that only trusted personnel have access to admin accounts, especially those with limited privileges that could exploit this flaw. Implement strict role-based access control (RBAC) policies and monitor admin API usage for unusual access patterns to the /unmanagedAttributes endpoint. Since no patch links are currently available, maintain close communication with Red Hat for timely updates and apply security patches as soon as they are released. Consider implementing additional logging and alerting on sensitive API calls to detect potential misuse. If feasible, restrict network access to the Keycloak Admin API to trusted management networks only. Review and minimize the use of sensitive custom attributes in user profiles or segregate sensitive data to reduce exposure. Finally, conduct internal training to raise awareness among administrators about the risk of privilege misuse.