MAL-2026-6907 Malicious code in chai-spycore (npm)
- Package
- chai-spycore
- Registry
- npm
What is MAL-2026-6907?
MAL-2026-6907 is a malicious package in chai-spycore, published on 7 Jul 2026.
Official description
Package republishes the chai-spies Chai plugin source verbatim (including original author header) under the near-identical name chai-spycore. package.json declares six runtime dependencies — fast-deep-equal, eventemitter3, lodash.clonedeep, chai-guard, is-plain-object, just-extend — but none of these are require()d anywhere in lib/spy.js or index.js. The legitimate chai-spies ships with zero runtime dependencies, so the additional deps are pulled into the installer's tree on npm install chai-spycore without serving any function in the package's own code. The non-mainstream chai-guard dependency is the most suspicious of the set and is the likely vehicle for any indirect code execution against the installer. Routing to human review to assess the name-confusion claim against chai-spies and to inspect chai-guard's contents.
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-2026-6907?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.
Sources
Also known as GHSA-w3fq-7xj5-8gmv.