GitLab patches CVE-2026-18252, command execution via the Duo Claude agent in CI

On August 26, 2026, GitLab shipped a fix for CVE-2026-18252, a flaw in the Duo Claude AI agent that lets an authenticated developer execute arbitrary commands in a CI context through user-controlled configuration. The lesson goes beyond GitLab: an AI agent wired into CI is a new execution surface, and the configuration it consumes is now part of the security boundary.