Malicious .git Configs Can Make Claude, Codex, Cursor, and Other AI Agents Run Attacker Code

Manifold Security has disclosed eight security flaws across seven command-line AI coding agents in which a repository's own Git configuration names a command that the agent runs on the developer's machine, four of them still unpatched at publication.

The command executes as the user, outside the agent's sandbox and without an approval prompt, and exploitation requires the repository to arrive as files with its .git directory intact, which a shared archive, a shared drive, a sync folder, or a USB stick preserves, whereas an ordinary clone does not.

Fixes have shipped for goose, Claude Code, and Cursor, while Hermes Agent, Qwen Code, Grok Build, and a second path in Claude Code were still executing repository-supplied commands when Manifold retested them on September 1.

OpenAI published three CVEs of its own the same day covering the identical class in Codex, credited to three unrelated research groups.

"The helper runs outside Codex's command sandbox and without a user-approval prompt, allowing attacker-controlled code to run with the user's privileges. The code can read, change, or delete the user's files and access other resources available to the user's account," OpenAI said in the record for CVE-2026-19592.