An issue has been discovered in GitLab EE affecting all versions starting from 12.2 prior to 14.10.5, 15.0 prior to 15.0.4, and 15.1 prior to 15.1.1. In GitLab, if a group enables the setting to restrict access to users belonging to specific domains, that allow-list may be bypassed if a Maintainer uses the 'Invite a group' feature to invite a group that has members that don't comply with domain allow-list.
CWE-863