A Denial of Service (DoS) issue has been discovered in GitLab CE/EE affecting all versions starting from 7.14.1 prior to 17.3.7, 17.4 prior to 17.4.4, and 17.5 prior to 17.5.2. A denial of service could occur upon importing maliciously crafted content using the Fogbugz importer.
https://hackerone.com/reports/2504059