Client-Side code injection through Feature Flag name in GitLab CE/EE starting with 11.9 allows a specially crafted feature flag name to PUT requests on behalf of other users via clicking on a link
https://hackerone.com/reports/1059557
https://gitlab.com/gitlab-org/gitlab/-/issues/293946
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22223.json