MAL-2026-13937 Malicious code in @ethers-js/contracts (npm)
Malicious package
Published
MAL-2026-13937 is a malicious package: @ethers-js/contracts (npm). Every version was published to cause harm.
Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.
Reference: https://insights.sbomify.com/MAL-2026-13937/ (Markdown: https://insights.sbomify.com/MAL-2026-13937/index.md)
- Package
- @ethers-js/contracts
- Registry
- npm
What is MAL-2026-13937?
MAL-2026-13937 is a malicious package in @ethers-js/contracts, published on 13 Aug 2026.
Official description
Package impersonates the ethers project (real releases publish under
ethers and @ethersproject/*, not @ethers-js). The postinstall lifecycle script in scripts/postinstall.js is obfuscated with \x-hex-encoded identifiers (require('fs'), require('https'), spawn('powershell',…)) and a base64-encoded download URL. On Windows, it decodes the URL to https://files.catbox.moe/7vixtr.zip, downloads the archive into %LOCALAPPDATA%\Microsoft<random>, extracts it via PowerShell Expand-Archive, and then invokes a bundled pythonw.exe against r.py with {detached:true, windowsHide:true} and.unref(), executing attacker-controlled code hidden from the user on npm install.What should I do about MAL-2026-13937?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.