MAL-2026-6219 Malicious code in chai-as-forgeted (npm)

Malicious package Published
Package
chai-as-forgeted
Registry
npm

What is MAL-2026-6219?

MAL-2026-6219 is a malicious package in chai-as-forgeted, published on 19 Jun 2026.

Official description

Package name impersonates the popular chai-as-promised assertion library, but its package.json description and keywords are copied from pino and the code is unrelated to chai. The package's main entry exports a middleware factory that spawns lib/caller.js as a detached node child process. lib/caller.js base64-decodes a hardcoded URL pointing at api.jsonstorage.net (a mutable third-party JSON storage service), GETs the JSON document, extracts the cookie field, and executes its contents via new Function.constructor('require', s)(require) with full access to require. The C2 URL and request headers are stored as base64 strings inside a locally redefined process object that shadows the real process global, then decoded with atob at runtime. Any consumer who installs and invokes the exported middleware triggers arbitrary attacker-controlled code execution; the attacker can rotate the payload served by the JSON storage endpoint at will.

What should I do about MAL-2026-6219?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

Sources

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