A vulnerability was discovered in GitLab versions before 13.1.10, 13.2.8 and 13.3.4. Under certain conditions GitLab was not properly revoking user sessions and allowed a malicious user to access a user account with an old password.
For GitLab before 13.0.12, 13.1.6, 13.2.3 after a group transfer occurs, members from a parent group keep their access level on the subgroup leading to improper access.
An authorization issue relating to project maintainer impersonation was identified in GitLab EE 9.5 and later through 13.0.1 that could allow unauthorized users to impersonate as a maintainer to perform limited actions.