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

2026-09-04

Manifold Security found eight flaws in seven coding agents. A received repository can use .git/config to trigger commands through core.fsmonitor, and the commands run with the developer's account permissions, outside sandbox controls and without approval. Fixes exist for goose, Codex, and one Claude Code path. Hermes Agent, Qwen Code, Grok Build, and another Claude Code path remained exposed.