Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.9 before 18.3.6, 18.4 before 18.4.4, and 18.5 before 18.5.2 that could have allowed an authenticated attacker to cause a denial of service condition by submitting specially crafted markdown content with nested formatting patterns.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GitLab | GitLab | 16.9 – < 18.3.6, 18.4 – < 18.4.4, 18.5 – < 18.5.2 | 18.3.6 |
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
- WID-SEC-2025-2587 GitLab: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 14, 2026
- NCSC-2025-0367 Kwetsbaarheden verholpen in GitLab NCSC-NL (Netherlands) · Nov 18, 2025
References
- https://about.gitlab.com/releases/2025/11/12/patch-release-gitlab-18-5-2-released/
- GitLab Issue #296257 issue-tracking permissions-required
- HackerOne Bug Bounty Report #3419588 technical-description exploit permissions-required