Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 17.7 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an authenticated user to execute arbitrary JavaScript in a user's browser due to improper sanitization of entity-encoded content in Mermaid diagrams.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GitLab | GitLab | 17.7 – < 18.8.7, 18.9 – < 18.9.3, 18.10 – < 18.10.1 | 18.8.7 |
Advisories 2
- NCSC-2026-0103 Kwetsbaarheden verholpen in GitLab NCSC-NL (Netherlands) · Mar 26, 2026
- WID-SEC-2026-0847 GitLab: Mehrere Schwachstellen BSI CERT-Bund (WID) · Mar 25, 2026
References
- HackerOne Bug Bounty Report #3566802 technical-description exploit permissions-required
- https://gitlab.com/gitlab-org/gitlab/-/work_items/591049
- https://about.gitlab.com/releases/2026/03/25/patch-release-gitlab-18-10-1-released/