The groups API in GitLab 6.x and 7.x before 7.4.3 allows remote authenticated guest users to modify ownership of arbitrary groups by leveraging improper permission checks.
GitLab Community Edition (CE) and Enterprise Edition (EE) before 8.17.8, 9.0.x before 9.0.13, 9.1.x before 9.1.10, 9.2.x before 9.2.10, 9.3.x before 9.3.10, and 9.4.x before 9.4.4 might allow remote attackers to execute arbitrary code via a crafted SSH URL in a project import.
GitLab before 8.14.9, 8.15.x before 8.15.6, and 8.16.x before 8.16.5 has XSS via a SCRIPT element in an issue attachment or avatar that is an SVG document.