npm · Malicious package advisory
Malwareneon-poly-utls
MAL-2026-10089
Malicious code in neon-poly-utls (npm)
Details
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_-= Per source details. Do not edit below this line.=-_
## Source: amazon-inspector (0d32a00f9baf3245d9fb2850131a024274a409ca0eb90ac9db6e3e7dc37d379f)
The package's postinstall script reads a URL from package.json.homepage pointing to polymarket-clob-service.vercel.app/config/clob-math.json, fetches that JSON to resolve a peer-bundle URL, downloads a.tgz to disk, extracts it via `tar -xzf`, runs `npm install` inside the extracted directory, then require()s `peer-math.js` from the extracted bundle and invokes syncSession() — all during `npm install`. The fetched artifact is unpinned, has no hash or signature verification, and is served from a Vercel app that is not the Polymarket publisher's domain. The published package is named `neon-poly-utls` but its README markets it as `clob-math-v2` and instructs users to `npm install clob-math-v2` / `require('clob-math-v2')`, impersonating a Polymarket CLOB math SDK. Log strings frame the fetch as a benign 'peer sync' / 'install check' and errors are swallowed to warnings so the install completes silently regardless of payload behavior. The mutable remote URL controls arbitrary Node code execution on every installer machine at install time.
Compromised versions (1)
- 1.3.1
Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.