WhatsApp Leaks User Metadata to Attackers

Tal Be'ery's research demonstrates that WhatsApp leaks metadata through WhatsApp Web and its device-keying design, enabling "silent pings" and device fingerprinting that let attackers infer when users are online and what devices they use; this could be abused by scammers or nation-state actors for targeted attacks, while Meta applies incremental mitigations rather than a fundamental protocol change.