When a team of cybersecurity researchers from the University of Vienna tested WhatsApp’s contact discovery feature, they uncovered something alarming: a design flaw that allowed them to enumerate phone numbers and public profile data of nearly 3.5 billion users worldwide.
No hacking or malware was required – researchers simply took advantage of the WhatsApp verification process that shows if a phone number is registered on its platform.
According to the University of Vienna team, the vulnerabi
