Auth bypass in GitLab
CVE-2026-4398
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (20.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- GitLab — versions 19.3.0
Weakness classification (CWE)
References
- docs.gitlab.com/releases/patches/patch-release-gitlab-19-3-1-released/ (Release Notes, Vendor Advisory)
- gitlab.com/gitlab-org/gitlab/-/work_items/600360 (Broken Link)
- hackerone.com/reports/3549150 (Permissions Required, technical-description, permissions-required, exploit)
Frequently asked questions
- What is CVE-2026-4398?
- CVE-2026-4398 is a medium-severity vulnerability in GitLab, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 5.4/10. Published 2026-04-08.
- How severe is CVE-2026-4398?
- Medium severity. CVSS v3 base score is 5.4 out of 10.