Major WhatsApp Flaw Exposes Phone Numbers of Over 3 Billion Users

Security experts have identified a major vulnerability in the instant messaging app WhatsApp, which has exposed phone numbers of over 3 billion users worldwide.

This privacy flaw could be exploited by cybercriminals to access users’ identities and related information on the popular app, potentially targeting them for malicious purposes.

The vulnerability was discovered by a team from the University of Vienna and SBA Research. It exists in WhatsApp’s contact discovery mechanism, which requests permission to match the phone numbers stored on users’ devices with the app’s central database.

Once granted, WhatsApp can identify which contacts are using the platform. However, cybercriminals could exploit this enumeration mechanism to extract phone numbers, profile photos, and users’ “About” status from devices.