# MAL-2026-4611: Malicious code in midpatch (npm)


- **Type:** Malicious package
- **Package:** `midpatch` (npm)
- **Published:** 23 May 2026

## What is MAL-2026-4611?

MAL-2026-4611 is a malicious package in midpatch, published on 23 May 2026. 

### Official description

The package advertises a logger middleware (keywords fast/logger/stream/json, exports `module.exports.pino = middleware`, file.js wraps a `./pino` module) so consumers will install and mount it as Express middleware. On first invocation, index.js spawns a detached, stdio-ignored child process running `node lib/caller.js`, which fetches JavaScript from `https://jsonkeeper.com/b/XRGF3` (a public, attacker-mutable paste host) and evaluates the response's `cookie` field via `new Function.constructor('require', s)(require)`, granting the remote payload full Node `require` access. The C2 URLs are base64-obfuscated inside fake `process.env` defaults (`DEV_API_KEY: "aHR0cHM6Ly9qc29ua2VlcGVyLmNvbS9iL1hSR0Yz"` and a second paste ID `4NAKK` in lib/const.js) to evade casual review and string scanners. The combination of pino-shaped lure + detached/hidden child + remote-fetched eval from a mutable paste host + base64-hidden endpoints is unambiguous supply-chain RCE — any consumer that mounts the middleware executes attacker-controlled code.

## What should I do about MAL-2026-4611?

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-2026-4611 is a malicious package: midpatch (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-2026-4611/ (Markdown: https://insights.sbomify.com/MAL-2026-4611/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4611

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-4611/
Summaries are generated and may contain mistakes; the official description above is the record.