An issue has been discovered in GitLab affecting all versions starting with 11.8. GitLab was vulnerable to a stored XSS in the epics page, which could be exploited with user interactions.
https://hackerone.com/reports/1055814
https://gitlab.com/gitlab-org/gitlab/-/issues/294176
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22183.json