MAL-2026-16347 Malicious code in radio-player-theme (npm)

radio-player-theme presents itself as a radio player theme. The published tarball contains three files: package.json, style.css (declared as main) and payload.js, which holds the package's only executable code.

payload.js is a browser payload. On execution it reads location.origin and document.cookie, extracts the value of a MANAGER-XSRF-TOKEN cookie, and sends the origin together with the collected state to an out-of-band callback domain under oastify.com by assigning it to an Image.src. It then issues a second authenticated request to a third-party manager API and writes the collected data to window.__radioXssProof.

The file carries a comment describing itself as a bug bounty proof of concept for a CSP bypass through a public CDN that serves npm packages. Regardless of that claim, the published package delivers working data-collection code to anyone who loads it, and the package has no other function.

The package declares no install hooks, so npm install alone does not execute the payload; the code runs when the file is loaded in a browser, which is what CDN delivery of an npm package enables.

Evidence: payload.js:7 holds the hardcoded callback domain; payload.js:13-19 perform the cookie read and the beacons. Determination: manual review of the published tarball (sha256 ddbb93aa9416c1c89cf15dc7627f4a816a1c31929238ed8608264546ba0df186).

[email protected] ships static browser assets (payload.js and a CSS file) whose content is a proof-of-concept CSS/XSS injection chain targeting a third-party service (manager.infomaniak.com), exfiltrating an origin string and an XSRF cookie preview to an Interactsh collaborator subdomain under oastify.com. The package declares no npm lifecycle scripts (preinstall/install/postinstall/prepare) and its main entry points at style.css, so nothing runs on npm install or on require(). The payload only has effect if the CSS/JS is loaded inside a victim's browser via the described injection chain against the third-party target, not against the developer who installs the package.

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.