Description

authentik is an open-source identity provider. Prior to 2026.2.6 and 2026.5.5, a diagnostic action on the LDAP Source API does not enforce the object-level read-authorization filter used by the rest of the API. Any party able to reach the API, including an unauthenticated client, can invoke the diagnostic action against a configured LDAP Source. The server then connects to the upstream directory using the source's configured bind credentials and returns a bounded set of directory entries. The response exposes the distinguished names of those entries and the names of the attributes present on them, revealing directory structure, naming conventions, and the existence of specific accounts and groups, but not attribute values. Deployments without a configured LDAP Source are not affected. This issue is fixed in versions 2026.2.6 and 2026.5.5.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.3",
  "pubDate": "2026-08-18T17:16:59.500Z",
  "pubdate": "2026-08-18T17:16:59.500Z",
  "executiveSummary": "An authorization bypass vulnerability exists within the LDAP Source API diagnostic action of authentik, an open-source identity provider, prior to versions 2026.2.6 and 2026.5.5. The vulnerability stems from the diagnostic action's failure to enforce the object-level read-authorization filter applied across the rest of the API.\nThis flaw allows any network-adjacent or remote party capable of reaching the API, including entirely unauthenticated clients, to invoke the diagnostic action against any configured LDAP Source. Upon invocation, the authentik server connects to the upstream directory leveraging the source's configured bind credentials and retrieves a bounded set of directory entries.\nThe resulting server response explicitly exposes the distinguished names (DNs) of those entries alongside the attribute names present on them. While attribute values are not disclosed, the information leakage reveals critical internal directory structure, naming conventions, and the existence of specific user accounts and security groups.\nDeployments lacking a configured LDAP Source are inherently unaffected by this issue. Risk implications center on reconnaissance capabilities, enabling attackers to map out internal Active Directory or LDAP topologies without prior authentication or privilege. The vulnerability is fully resolved in authentik versions 2026.2.6 and 2026.5.5 through proper enforcement of read-authorization filters on the affected diagnostic endpoint.",
  "technicalDetails": "The vulnerability resides in the LDAP Source API diagnostic action component of authentik. The root cause of the security defect is an authorization enforcement omission: while standard endpoints within the LDAP Source API properly evaluate and enforce object-level read-authorization filters, the specific diagnostic action bypasses these access control checks entirely.\nThe vulnerable component is exposed via the API network interface and is reachable by arbitrary callers. Consequently, the authentication requirement for this specific action is effectively null, allowing unauthenticated clients to interact with the endpoint. No elevated privileges are required by the calling party to trigger the vulnerable functionality.\nThe attack flow proceeds as follows: First, an unauthenticated attacker establishes network connectivity to the authentik API endpoint hosting the LDAP Source diagnostic action. Second, the attacker sends a crafted request invoking the diagnostic action against a valid, pre-configured LDAP Source. Third, upon receiving the request, the authentik server processes it by utilizing the upstream directory's pre-configured bind credentials to authenticate against the external LDAP or Active Directory server. Fourth, the upstream directory returns a bounded set of directory entries to the authentik server. Fifth, the authentik server serializes and returns this data in the API response without verifying whether the requesting client possesses authorization to view the source objects.\nThe payload behavior and post-exploitation impact involve the disclosure of structural metadata rather than direct credential theft or execution. The response data exposes sensitive internal reconnaissance information, including the distinguished names (DNs) of directory entries and the precise names of attributes populated on those objects. Although attribute values are withheld, an attacker leverages this structural insight to map naming conventions, deduce organizational hierarchies, and confirm the explicit existence of specific user accounts and security groups. This intelligence facilitates subsequent targeted attacks against the organization's identity infrastructure."
}