Vulnerability MAL-2026-17442

This package is a fork of the Baileys WhatsApp Web library (npm) and belongs to the "PhantomSub" family described by OX Security in September 2026: the publisher injected code that, without the installer asking, uses the installer's own authenticated WhatsApp session to subscribe that account to WhatsApp Channels (newsletters) the publisher chose, by sending the WhatsApp w:mex FOLLOW query (query_id 7871414976211147) for each target channel JID.

package/lib/Socket/newsletter.js lines 53-61 register a connection.update handler that, as soon as the connection opens, sends a FOLLOW query (xwa2_newsletter_join_v2) for the plain-literal JID SAIRIDEV_NEWSLETTER = '120363408385315496@newsletter' (cited line 58: await executeWMexQuery({ newsletter_id: SAIRIDEV_NEWSLETTER }, QueryIds.FOLLOW, XWAPaths.xwa2_newsletter_join_v2);). There is no opt-out. The package README states "No auto-follow channel (newsletter) behavior", which the shipped code contradicts.

Line numbers refer to version 1.0.0.

Static review of the published tarball(s) found no code that sends WhatsApp credentials or session keys off-host, no install-time payload (the only install hook is Baileys' stock Node.js version check in engine-requirements.js), and no persistence; the payload runs when an application creates a WhatsApp socket with the library. The harm is the covert use of the victim's account to inflate the publisher's channel subscribers.

SHA-256 of the published npm tarball(s): 1.0.0: 7afa059f55b913a2b78dfcaf0a14adec87a494e166b9c1b4308df9f1eca580f0.