# MAL-2026-11033: Malicious code in eth-codergen (npm)


- **Type:** Malicious package
- **Package:** `eth-codergen` (npm)
- **Published:** 23 Jul 2026
- **Also known as:** GHSA-87w3-vjw9-8h4w

## What is MAL-2026-11033?

MAL-2026-11033 is a malicious package in eth-codergen, published on 23 Jul 2026. 

### Official description

The package is advertised as an Ethereum ABI code generator but its `index.js` is a verbatim copy of the unrelated `mongoose-lean-hooks` plugin. Appended to the same line as `module.exports = leanhooksPlugin;` (padded with whitespace to push it off-screen) is a top-level `Function("tQ4eR5v",...)` call whose body is a custom hex/XOR-mixer decoder (constants 0x9e3779b9, 0x243f6a88, 0x6a09e667) that reconstructs an opaque payload from an encoded byte array and executes it. The obfuscated loader runs automatically whenever a consumer calls `require('eth-codergen')`, giving the publisher arbitrary code execution in the consumer's Node.js process. The package name differs by one letter from the legitimate `eth-codegen` package, and the README even instructs `npm install --save-dev eth-codegen`, indicating the package is positioned to catch developers who mistype the real package name. No Ethereum/ABI codegen functionality is present in the shipped code.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-11033?

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-2026-11033 is a malicious package: eth-codergen (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-2026-11033/ (Markdown: https://insights.sbomify.com/MAL-2026-11033/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-11033

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-11033/
Summaries are generated and may contain mistakes; the official description above is the record.