Under very specific conditions a user could be impersonated using Gitlab shell. This vulnerability affects GitLab CE/EE 13.1 and later through 14.1.2, 14.0.7 and 13.12.9.
https://hackerone.com/reports/1087806
https://gitlab.com/gitlab-org/gitlab/-/issues/300265
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-22254.json