CVE-2026-4398 Authorization Bypass Through User-Controlled Key in GitLab

Medium 5.4 Published 27 Aug 2026 Updated 28 Aug 2026

Authenticated users can assign unauthorized compliance frameworks to their projects due to missing namespace validation on self-managed instances.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-4398?

CVE-2026-4398 is a medium-severity missing authorization vulnerability in Gitlab Gitlab, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

Weakness: CWE-639

Which versions are affected by CVE-2026-4398?

1 open source package ship an affected version, including gitlab. It affects 1 product.

Package	Affected	Fixed in
`gitlab` Bitnami	From `18.3.0`	`19.1.7, 19.2.5, 19.3.1`

Products include Gitlab Gitlab.

How do I fix CVE-2026-4398?

Upgrade gitlab to a fixed version for your release line: 19.1.7, 19.2.5 or 19.3.1.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-4398 being exploited?

There is no known exploitation of CVE-2026-4398 in the wild and no public exploit code.

All Gitlab Gitlab vulnerabilities

Sources

Also known as BIT-gitlab-2026-4398, GHSA-hpxp-rx7c-457j, MINI-jrcf-rxrc-5gr3, MINI-rj5x-294g-53hf, MINI-x96r-8x9x-cg57.