Improper group membership validation when deleting a user account in GitLab >=7.12 allows a user to delete own account without deleting/transferring their group.
https://hackerone.com/reports/503823
https://gitlab.com/gitlab-org/gitlab/-/issues/27231
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13335.json