goauthentik up to 2025.12.4/2026.2.2 /api/v3/core/users/ change_user privileges management

Summaryinfo

A vulnerability was found in goauthentik authentik up to 2025.12.4/2026.2.2. It has been rated as critical. Affected by this issue is the function change_user of the file /api/v3/core/users/. The manipulation leads to privileges management. This vulnerability is uniquely identified as CVE-2026-40172. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, has been found in goauthentik authentik up to 2025.12.4/2026.2.2. This issue affects the function change_user of the file /api/v3/core/users/. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-40172 since 04/09/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 2025.12.5 or 2026.2.3 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Vendor

• goauthentik

Name

• authentik

Version

• 2025.12.0
• 2025.12.1
• 2025.12.2
• 2025.12.3
• 2025.12.4
• 2026.2.0
• 2026.2.1
• 2026.2.2

Website

• Product: https://github.com/goauthentik/authentik/

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