yukistage

GHSA-vm4r-7w2f-r5x9

Malicious code in yukistage (npm)

Details

**Severity:** Critical

**Affected versions:** `= 1.1.7`

yukistage is a fork of the Baileys WhatsApp Web library that silently subscribes the installer's own WhatsApp account to WhatsApp Channels chosen by the publisher. When the socket connects, code in lib/Socket/newsletter.js sends the WhatsApp w:mex FOLLOW query for the channel ID(s) 120363400911374213@newsletter, using the victim's authenticated session and without telling them. Same behaviour as the PhantomSub family (MAL-2026-17342).

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/f8bd377e5c522af8e1a7cf92b0cd17dcdba7a45f/osv/malicious/npm/yukistage/MAL-2026-19042.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/f8bd377e5c522af8e1a7cf92b0cd17dcdba7a45f/osv/malicious/npm/yukistage/MAL-2026-19042.json
- https://www.npmjs.com/package/yukistage
- https://www.ox.security/blog/phantomsub-malicious-npm-campaign-secretly-adds-users-to-whatsapp-spam-channels
- https://github.com/advisories/GHSA-vm4r-7w2f-r5x9

Compromised versions (1)

= 1.1.7

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.