Researchers uncovered a major WhatsApp vulnerability allowing anyone to check if nearly every phone number worldwide uses the app — just by adding it to contacts.
How the Flaw Worked
- Simple test: Add a number to your contacts; WhatsApp reveals if it's active, plus profile photos and names.
- Team scripted it to scan 3.5 billion combinations, exposing users globally.
Privacy Risks
This flaw turned phone numbers into identifiable profiles, raising serious data privacy concerns.
Meta's Response
- Quick fix: Added query limits to block mass scanning.
- No evidence of active criminal exploitation, per Meta.
Source: [9to5Mac](https://9to5mac.com)
