# MAL-2026-13937: Malicious code in @ethers-js/contracts (npm)


- **Type:** Malicious package
- **Package:** `@ethers-js/contracts` (npm)
- **Published:** 13 Aug 2026

## 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.

## Fix prompt for AI coding agents

```text
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)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13937

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-13937/
Summaries are generated and may contain mistakes; the official description above is the record.