# MAL-2026-10050: Malicious code in chai-defender (npm)


- **Type:** Malicious package
- **Package:** `chai-defender` (npm)
- **Published:** 9 Jul 2026
- **Also known as:** GHSA-hqh4-jccw-jxg6

## What is MAL-2026-10050?

MAL-2026-10050 is a malicious package in chai-defender, published on 9 Jul 2026. 

### Official description

On require('chai-defender'), index.js invokes launchDeflectBootstrap() which spawns a detached background node process running lib/caller.js. That process loads lib/initstate.js, which performs an HTTP GET against a hardcoded remote endpoint (http://check-server-state.vercel.app/server/v2) and passes the response body into `new Function('require', <response>)(require)`, executing attacker-controlled JavaScript with access to Node's require in the installer's process. The package presents itself as a Chai assertions plugin ('Security-focused Chai assertions'), but this fetch-and-exec behavior is unrelated to any assertion functionality. The lib/ directory is padded with files whose names mimic the pino logger project (multistream.js, transport.js, redaction.js, levels.js, symbols.js, worker.js) and reference a non-existent./flowlimit.js module; these files are not wired into index.js and appear to exist to make the package look substantial while the real payload is lib/const.js + lib/initstate.js. Plain HTTP transport additionally exposes the eval channel to in-path payload injection. Any project that requires this package hands remote code execution to whoever controls check-server-state.vercel.app.

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-2026-10050?

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-2026-10050 is a malicious package: chai-defender (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-2026-10050/ (Markdown: https://insights.sbomify.com/MAL-2026-10050/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-10050

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-10050/
Summaries are generated and may contain mistakes; the official description above is the record.