CVE-2026-40166 PUBLISHED

authentik: Non-admin user can retrieve confidential OAuth client_secret via /api/v3/oauth2/access_tokens/

Assigner: GitHub_M
Reserved: 09.04.2026 Published: 22.05.2026 Updated: 22.05.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N
CVSS Score: 7.1

Product Status

Vendor goauthentik
Product authentik
Versions
  • Version < 2025.12.5 is affected
  • Version >= 2026.2.0-rc1, < 2026.2.3 is affected

References

Problem Types

  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-863: Incorrect Authorization CWE