Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 19.1 before 19.2.8, 19.3 before 19.3.5, and 19.4 before 19.4.2 that, under certain conditions, could have allowed an authenticated user to execute arbitrary JavaScript in the context of other users' browser sessions via a specially crafted repository, due to improper sanitization of HTML attributes in syntax-highlighted output.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GitLab | GitLab | 19.1 – < 19.2.8, 19.3 – < 19.3.5, 19.4 – < 19.4.2 | 19.2.8 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | gitlab | No fix yet | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | gitlab-runner-19.2 +5 | No fix yet | — |
| Wolfi rolling | gitlab-runner-19.3 +5 | 19.3.5-r0 | — |
Advisories 2
- WID-SEC-2026-3858 GitLab: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
- NCSC-2026-0414 Kwetsbaarheden verholpen in GitLab NCSC-NL (Netherlands) · Oct 13, 2026
References
- https://gitlab.com/gitlab-org/gitlab/-/work_items/629523
- HackerOne Bug Bounty Report #3936831 technical-description exploit permissions-required
- https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-4-2-released/