MAL-2026-16339 Malicious code in pf25133 (npm)

Malicious package Published
Package
pf25133
Registry
npm

What is MAL-2026-16339?

MAL-2026-16339 is a malicious package in pf25133, published on 21 Sep 2026.

Official description

The package's declared main module index.js is an IIFE that reads document.cookie, fetches a hardcoded list of application paths, extracts flag-shaped patterns from the responses, and POSTs the aggregated data as JSON to a hardcoded webhook.site collector URL (https://webhook.site/c4e39647-bfb8-47ef-b6d4-a112aacc6cd1). The behavior is unconditional on load and the destination is not configurable. webhook.site is a generic anonymous request-bin service unrelated to any legitimate first-party endpoint, and the package ships no functionality other than this collection payload.

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-2026-16339?

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

Sources

Also known as GHSA-8f7g-cf69-g5p8.

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