A denial of service in user's profile page is found starting with GitLab CE/EE 8.0 that allows attacker to reject access to their profile page via using a specially crafted username.
https://hackerone.com/reports/475098
https://gitlab.com/gitlab-org/gitlab/-/issues/26295
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22231.json