In all versions of GitLab CE/EE since version 12.0, a lower privileged user can import users from projects that they don't have a maintainer role on and disclose email addresses of those users.
https://hackerone.com/reports/542539
https://gitlab.com/gitlab-org/gitlab/-/issues/28440
https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39892.json