GitLab has remediated an issue in GitLab CE/EE affecting all versions from 12.3 before 18.9.6, 18.10 before 18.10.4, and 18.11 before 18.11.1 that under certain conditions could have allowed an authenticated user to cause denial of service when importing issues due to improper input validation.
https://hackerone.com/reports/3518743
https://gitlab.com/gitlab-org/gitlab/-/work_items/588200
https://about.gitlab.com/releases/2026/04/22/patch-release-gitlab-18-11-1-released/