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.
https://hackerone.com/reports/3446641
https://gitlab.com/gitlab-org/gitlab/-/work_items/584490
https://about.gitlab.com/releases/2026/05/13/patch-release-gitlab-18-11-3-released/