GitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.9 before 18.3.6, 18.4 before 18.4.4, and 18.5 before 18.5.2 that could have allowed an authenticated attacker to cause a denial of service condition by submitting specially crafted markdown content with nested formatting patterns.
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.