In all versions of GitLab CE/EE since version 8.0, access tokens created as part of admin's impersonation of a user are not cleared at the end of impersonation which may lead to unnecessary sensitive info disclosure.
In all versions of GitLab CE/EE since version 7.7, the application may let a malicious user create an OAuth client application with arbitrary scope names which may allow the malicious user to trick unsuspecting users to authorize the malicious client application using the spoofed scope name and description.
In all versions of GitLab CE/EE since version 8.0, a DNS rebinding vulnerability exists in Fogbugz importer which may be used by attackers to exploit Server Side Request Forgery attacks.
A stored Cross-Site Scripting vulnerability in the GitLab Flavored Markdown in GitLab CE/EE version 8.4 and above allowed an attacker to execute arbitrary JavaScript code on the victim's behalf.
Missing authentication in all versions of GitLab CE/EE since version 7.11.0 allows an attacker with access to a victim's session to disable two-factor authentication
In all versions of GitLab CE/EE since version 8.0, when an admin uses the impersonate feature twice and stops impersonating, the admin may be logged in as the second user they impersonated, which may lead to repudiation issues.
In all versions of GitLab CE/EE, an attacker with physical access to a user’s machine may brute force the user’s password via the change password function. There is a rate limit in place, but the attack may still be conducted by stealing the session id from the physical compromise of the account and splitting the attack over several IP addresses and passing in the compromised session value from these various locations.