MAL-2026-4556 Malicious code in express-enrouten-async (npm)
- Package
- express-enrouten-async
- Registry
- npm
What is MAL-2026-4556?
MAL-2026-4556 is a malicious package in express-enrouten-async, published on 22 May 2026.
Official description
Package name mimics the legitimate express-enrouten route-discovery library, but the shipped index.js only hardcodes two demo routes rather than implementing automatic route discovery. The malicious mechanism is in package.json, which declares "node-fetch": "https://registry.ctzbg.com/express-enrouten-async/node-fetch" — a direct URL dependency pointing at a third-party, non-npm registry under a path namespaced to this package. On npm install, npm fetches and installs whatever tarball that URL serves as the installer's node-fetch, so any code requiring node-fetch in the host application loads attacker-controlled, unpinned, mutable bytes from a non-publisher domain. This is dependency-confusion-style supply-chain attack: the lookalike package name lures the install, and the URL-pinned fake node-fetch is the delivery vehicle for arbitrary code into the installer's dependency tree.
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-2026-4556?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.
Sources
Also known as GHSA-25jv-xr7c-mx67.