MAL-2026-16473 Malicious code in sea-baileys (npm)

sea-baileys is a fork of the Baileys WhatsApp Web library. Its package.json remaps the libsignal import specifier to npm:@otaxayun/libsignal-node@latest — an unrelated maintainer's package pinned to the mutable latest dist-tag rather than a fixed version or integrity hash. lib/Signal/libsignal.js routes the installer's Signal Protocol identity private key, signed pre-key private key, session records and sender keys through this dependency, so whatever code @otaxayun/libsignal-node resolves to at install time handles the consumer's WhatsApp cryptographic identity and message stream. Because the tag is mutable and owned by a third party outside the sea-baileys publisher, a single publish under that name replaces the crypto implementation on every subsequent npm install. Separately, lib/Utils/messages-media.js's prepareWAMessageMedia unconditionally attaches a hardcoded annotations block referencing the newsletter JID 120363409928671192@newsletter ("HOSHINO AI INFORMATION") to every outgoing media message when the caller does not supply annotations, silently modifying consumer-generated WhatsApp payloads to advertise the fork author's channel.