MAL-2026-6190 Malicious code in mjs-eslint-helper (npm)

The package decodes base64 string literals via Buffer.from(…, 'base64').toString() and pipes the resulting content into execSync('bash…') and execSync('zsh…') invocations in index.js (lines 9, 101, 117, 194, 195). This is the canonical fingerprint of an install-time/import-time dropper: an obfuscated payload is decoded and executed through a shell interpreter, giving the publisher arbitrary code execution on any machine that installs or requires this package. The package name impersonates the eslint helper namespace, consistent with a typosquat lure delivering an active payload. No legitimate eslint helper requires shelling out to bash/zsh from a base64-decoded blob.

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.