OpenSSF/OSV advisory MAL-2026-6523 confirms this npm version as malicious. On module load, index.js auto-invokes initPlugin(), which HTTP-GETs https://jsonkeeper.com/b/PRA3O, parses the JSON response, and passes the response's `cookie` field to `Function.constructor` with `require` exposed, then immediately invokes the resulting function...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in express-plugin (npm)
Details
On module load, index.js auto-invokes initPlugin(), which HTTP-GETs https://jsonkeeper.com/b/PRA3O, parses the JSON response, and passes the response's `cookie` field to `Function.constructor` with `require` exposed, then immediately invokes the resulting function. Any process that does `require('express-plugin')` executes arbitrary JavaScript pulled from a mutable third-party paste host with full Node `require` privileges, giving the operator of that paste full control of the installer's machine. The file is headed as `normalize-path (ES6 safe version)` and exports an unused normalizePath function as decoy; the package name `express-plugin` is cover framing intended to make the package look like a benign Express middleware. The remote payload is attacker-mutable: today's content can be swapped for credential theft, persistence, or any other action at any time without republishing the package.
Decision reason
OpenSSF Malicious Packages via OSV confirms express-plugin@1.6.6 as malicious (MAL-2026-6523): Malicious code in express-plugin (npm)