An issue has been discovered in GitLab affecting all versions starting with 13.0. Confidential issue titles in Gitlab were readable by an unauthorised user via branch logs.
https://hackerone.com/reports/916340
https://gitlab.com/gitlab-org/gitlab/-/issues/227040
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22188.json