GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.7 before 18.7.4, and 18.8 before 18.8.4 that could have allowed an unauthenticated user to cause denial of service through CPU exhaustion by submitting specially crafted markdown files that trigger exponential processing in markdown preview.
Credits
Thanks [maksyche](https://hackerone.com/maksyche) for reporting this vulnerability through our HackerOne bug bounty program