An issue has been discovered in GitLab CE/EE affecting all versions from 17.6 before 18.3.6, 18.4 before 18.4.4, and 18.5 before 18.5.2, that, under specific conditions, could have allowed unauthorized users to view confidential branch names by accessing project issues with related merge requests.
https://about.gitlab.com/releases/2025/11/12/patch-release-gitlab-18-5-2-released/