Vulnerability Description
authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, authenticated non-admin users with at least one OAuth2 access token can retrieve the client_secret of confidential OAuth2 providers they have previously authenticated against, exposing sensitive information to users without the correct permissions. This logic is GET /api/v3/oauth2/access_tokens/. The API response includes a nested provider object containing client_id and client_secret for providers configured with client_type: confidential, which should not be accessible to low-privilege users. This issue has been fixed in versions 2025.12.5 and 2026.2.3.
Related Weaknesses (CWE)
References
- https://github.com/goauthentik/authentik/releases/tag/version%2F2025.12.5
- https://github.com/goauthentik/authentik/releases/tag/version%2F2026.2.3
- https://github.com/goauthentik/authentik/security/advisories/GHSA-hhpc-rqgm-pxj4
FAQ
What is CVE-2026-40166?
CVE-2026-40166 is a documented vulnerability. authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, authenticated non-admin users with at least one OAuth2 access token can retrieve the cl...
How severe is CVE-2026-40166?
CVSS scoring is not yet available for CVE-2026-40166. Check NVD for updates.
Is there a patch for CVE-2026-40166?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.