CVE-2026-40172
HighSummary
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 assigning arbitrary groups, including groups with superuser privileges, leading to privilege escalation.
Risk Assessment
Organizations may be exposed to unauthorized access to administrator accounts, potentially leading to serious security breaches and data loss.
Recommendation
It is recommended to upgrade to versions 2025.12.5 or 2026.2.3 to mitigate this vulnerability.
Original NVD description (English source)
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.