XSS in GitLab
CVE-2026-84739
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 13.11 before 19.2.7, 19.3 before 19.3.3, and 19.4 before 19.4.1 that under certain conditions could have allowed an authenticated user to execute arbitrary JavaScript in the context of another user's browser session due to improper sanitization of path components in the merge request diff viewer.
Vulnerability class: XSS (Cross-Site Scripting)
Published .
CVSS v3 metric
CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- gitlab.com/gitlab-org/gitlab/-/work_items/627316
- hackerone.com/reports/3938482 (technical-description, permissions-required, exploit)
- docs.gitlab.com/releases/patches/patch-release-gitlab-19-4-1-released/
Frequently asked questions
- What is CVE-2026-84739?
- CVE-2026-84739 is a high-severity vulnerability in GitLab, classified under Cross-site Scripting. CVSS score: 8.7/10. Published 2026-09-29.
- How severe is CVE-2026-84739?
- High severity. CVSS v3 base score is 8.7 out of 10.