An input validation and output encoding issue was discovered in the GitLab email notification feature which could result in a persistent XSS. This was addressed in GitLab 12.1.2, 12.0.4, and 11.11.6.
An input validation problem was discovered in the GitHub service integration which could result in an attacker being able to make arbitrary POST requests in a GitLab instance's internal network. This vulnerability was addressed in 12.1.2, 12.0.4, and 11.11.6.