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, the PATCH /api/v3/core/users/{pk}/ API allows a caller with change_user on a target user to assign arbitrary groups through UserSerializer, including groups with is_superuser=True, without requiring enable_group_superuser, leading to privilege escalation. This bypasses the stricter permission model enforced in group-management paths and enables delegated user-management permissions to escalate target users to administrator-equivalent privilege. Users with permissions to update groups or permissions to update users are able to add themselves or other users they have permissions on to users which have superuser permissions. This issue has been fixed in versions 22025.12.5 and 2026.2.3.
CVSS Score
HIGH
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-h6x7-hjjc-wjc9
FAQ
What is CVE-2026-40172?
CVE-2026-40172 is a vulnerability with a CVSS score of 8.1 (HIGH). authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, the PATCH /api/v3/core/users/{pk}/ API allows a caller with change_user on a target use...
How severe is CVE-2026-40172?
CVE-2026-40172 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40172?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.