Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that under certain circumstances, could have allowed an unauthenticated user to inject arbitrary scripts into the Mermaid sandbox UI.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GitLab | GitLab | 16.2 – < 18.7.5, 18.8 – < 18.8.5, 18.9 – < 18.9.1 | 18.7.5 |
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 | — |
Advisories 2
- NCSC-2026-0072 Kwetsbaarheden verholpen in GitLab NCSC-NL (Netherlands) · Feb 27, 2026
- WID-SEC-2026-0529 GitLab: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 25, 2026
References
- GitLab Issue #585371 issue-tracking permissions-required
- HackerOne Bug Bounty Report #3473276 technical-description exploit permissions-required
- https://about.gitlab.com/releases/2026/02/25/patch-release-gitlab-18-9-1-released/