Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.5 before 18.9.7, 18.10 before 18.10.6, and 18.11 before 18.11.3 that could have allowed an unauthenticated user to cause denial of service by sending specially crafted JSON payloads due to insufficient input validation.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GitLab | GitLab | 18.5 – < 18.9.7, 18.10 – < 18.10.6, 18.11 – < 18.11.3 | 18.9.7 |
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-2026-0161 Kwetsbaarheden verholpen in GitLab door GitLab Inc. NCSC-NL (Netherlands) · May 15, 2026
- WID-SEC-2026-1523 GitLab: Mehrere Schwachstellen BSI CERT-Bund (WID) · May 14, 2026
References
- HackerOne Bug Bounty Report #3446641 technical-description exploit permissions-required
- https://gitlab.com/gitlab-org/gitlab/-/work_items/584490
- https://about.gitlab.com/releases/2026/05/13/patch-release-gitlab-18-11-3-released/