Vulnerability · Published Aug 27, 2026 · Assigned by GitLab

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

Medium 5.4

In plain English

A medium-severity authorization bypass via user-controlled key in GitLab from GitLab. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.2%top 84.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
GitLab	GitLab	18.3 – before 19.1.719.2 – before 19.2.519.3 – before 19.3.1

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

References

HackerOne Bug Bounty Report #3549150 technical-description, exploit, permissions-required
https://gitlab.com/gitlab-org/gitlab/-/work_items/600360
https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-3-1-released/