CVE-2026-84739

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab

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.

Affected

GitLab

CVSS v3.1 GITLAB

8.7 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS

0.47% chance of exploitation in the next 30 days, 39th percentile

Published

2026-09-29

Proof-of-concept exploits (1)

• https://hackerone.com/reports/3938482

Security advisories

• https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-4-1-released

References

• CVE Record
• NVD entry