CVE-2026-84739

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

State: Published
Severity: 8.7 High
Published: Sep 29, 2026
Updated: Sep 29, 2026
Reserved: Sep 2, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	8.7 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N	GitLab

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
GitLabGitLab	13.11 to before 19.2.7Affected 19.3 to before 19.3.3Affected 19.4 to before 19.4.1Affected

References

https://gitlab.com/gitlab-org/gitlab/-/work_items/627316
HackerOne Bug Bounty Report #3938482technical-descriptionexploitpermissions-required
https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-4-1-released/

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