Malicious code in wailib (npm)

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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/messages-recv.js` lines 45-72 define a char-code decoder (`qvnr`) and use it to build two channel JIDs, `120363428355171197@newsletter` and `120363425751417260@newsletter`, and the method names `newsletterFollow` (`pzha`, cited line 62: `const pzha = qvnr([`) and `newsletterMute` (`wjcf`, line 68), so neither the JIDs nor the method names appear in the source as text. Lines 1125-1140, in the `connection.update` handler, wait 30 seconds after the connection opens and then, for each JID, call `sock[pzha](id)` to follow the channel and, 3 seconds later, `sock[wjcf](id)` to mute it, so the victim is not notified of the channel's posts. There is no opt-out. The README (Portuguese) states "Sem auto-follow de canais — removida a rotina que seguia canais automaticamente apos conectar" ("No channel auto-follow — the routine that followed channels automatically after connecting was removed"), which the shipped code contradicts. The code is derived from `noxleyss` (MAL-2026-17402), whose name it still uses in `package/lib/Utils/generics.js`. 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: `e762bd70253081e1f523e929509e8bd5ff005feaaec6580f8f8b95ee84085920`.

Source published

1 Oct 2026 23:05:37 UTC

Source modified

2 Oct 2026 05:30:06 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.