An issue has been discovered in GitLab CE/EE affecting all versions before 15.0.5, all versions starting from 15.1 before 15.1.4, all versions starting from 15.2 before 15.2.1. It may be possible to gain access to a private project through an email invite by using other user's email address as an unverified secondary email.
https://hackerone.com/reports/1517554
https://gitlab.com/gitlab-org/gitlab/-/issues/356665
https://gitlab.com/gitlab-org/cves/-/blob/master/2022/CVE-2022-2326.json