# MAL-2026-5901: Malicious code in chai-as-polished (npm)


- **Type:** Malicious package
- **Package:** `chai-as-polished` (npm)
- **Published:** 16 Jun 2026
- **Also known as:** GHSA-jpr9-h23w-g7gg

## What is MAL-2026-5901?

MAL-2026-5901 is a malicious package in chai-as-polished, published on 16 Jun 2026. 

### Official description

Package name is a one-edit typosquat of the widely-used chai-as-promised, but the shipped code is unrelated to chai. The exported middleware spawns a detached, unref'd child process running lib/initializeCaller.js. That file constructs a fake `process.env` containing three base64-encoded fields which decode to the URL https://tomato-brunhilda-40.tiiny.site/index.json and the header `x-secret-key: _`, fetches that URL via axios, and passes `response.data.cookie` to `new Function.constructor('require', response)(require)` — executing arbitrary attacker-supplied JavaScript with the installer's Node `require` available. The base64 staging of the URL and header has no functional purpose other than to hide the destination from cursory review. tiiny.site is an anonymous static-hosting service whose contents the author can change at any time, so the executed payload is fully attacker-controlled and mutable. Triggering requires a consumer to invoke the package's middleware, which is the documented entry point for anyone deceived by the name into installing it.

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-2026-5901?

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-2026-5901 is a malicious package: chai-as-polished (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-2026-5901/ (Markdown: https://insights.sbomify.com/MAL-2026-5901/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5901

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-5901/
Summaries are generated and may contain mistakes; the official description above is the record.