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 EE since version 8.13, an endpoint discloses names of private groups that have access to a project to low privileged users that are part of that project.
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.
In all versions of GitLab CE/EE since version 8.15, a DNS rebinding vulnerability in Gitea Importer may be exploited by an attacker to trigger Server Side Request Forgery (SSRF) 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.