Threat
MALFEX npm & AGENTS.md Prompt Injection: AI Coding Agent Attack 2026
First reported · Discovered aviatrix.ai
Page published
Earliest dated coverage: 26 Oct 2026 · First observed: 27 Oct 2026 · Latest dated coverage: 26 Oct 2026
Coverage timeline
Single-source incident — one report is available.
Why it matters
The reported AGENTS.md attack shows how attacker-controlled local instruction files can redirect coding agents into installing malware, making instruction discovery and package-installation permissions important defensive boundaries.
Aviatrix reports that Forever Security discovered a malicious AGENTS.md file in a developer’s Downloads folder that instructed an AI coding agent to install function-color, an npm package linked to the MALFEX campaign. The reported attack uses browser-planted instructions to redirect trusted coding agents into a downloader chain that executes a Windows payload.