GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that could have allowed an unauthenticated user to cause regular expression denial of service by sending specially crafted input to a merge request endpoint under certain conditions.
Weakness
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Gitlab | Gitlab | 9.2.0 (including) | 18.7.5 (excluding) |
| Gitlab | Gitlab | 18.8.0 (including) | 18.8.5 (excluding) |
| Gitlab | Gitlab | 18.9.0 (including) | 18.9.0 (including) |
| Gitlab | Ubuntu | esm-apps/xenial | * |
Extended Description
Attackers can create crafted inputs that
intentionally cause the regular expression to use
excessive backtracking in a way that causes the CPU
consumption to spike.