GitLab has remediated an issue in GitLab CE/EE affecting all versions from 5.2 prior to 18.2.8, 18.3 prior to 18.3.4, and 18.4 prior to 18.4.2 that could have allowed an authenticated attacker to create a denial of service condition by configuring malicious webhook endpoints that send crafted HTTP responses.
https://about.gitlab.com/releases/2025/10/08/patch-release-gitlab-18-4-2-released/