If this package is installed
Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.
Details
yuuki-baileys 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 Yuuki-baileys/lib/Socket/newsletter.js, lib/Socket/newsletter.js sends the WhatsApp w:mex FOLLOW query for the channel ID(s) 120363406005175144@newsletter, using the victim's authenticated session and without telling them. Same behaviour as the PhantomSub family (MAL-2026-17342).