Archive · 21 Nov 2025
WhatsApp Data Exposure: 3.5 Billion Users Affected by Unpatched Vulnerability
A big study found a hole in WhatsApp that let people see personal info of almost everyone using it.
This info wasn't secret, but it could still tell people a lot about you.
WhatsApp's owner, Meta, fixed the problem after they heard about it.
No one knows if anyone used this hole to do something bad.
A study from the University of Vienna found a severe vulnerability in WhatsApp
Nearly 3.5 billion users' data exposed, including profile photos, 'about' texts, and timestamps
Researchers could generate 100 million queries per hour, harvesting data from 245 countries
The flaw allowed inference of user's operating system, WhatsApp usage duration, and linked devices
Meta patched the issue after being informed, with no evidence of malicious exploitation
- Who
- University of Vienna researchers, Meta (WhatsApp's owner)
- What
- Discovered and patched a severe vulnerability in WhatsApp
- When
- The vulnerability was present until patched, study published recently
- Where
- Worldwide, affecting users across 245 countries
- Why
- To harvest user data at an extraordinary speed and scale
Researchers' View
Meta's View
Vulnerability Existence
Researchers' View
The vulnerability was severe and allowed large-scale data harvesting
Meta's View
The issue was a new enumeration technique that bypassed existing safeguards
Data Sensitivity
Researchers' View
Exposed data could reveal much more about users than initially thought
Meta's View
Harvested data consisted only of details already visible to anyone with access to a phone number
- Affected Users
- Nearly 3.5 billion
- Data Exposed
- Profile photos, 'about' texts, timestamps, operating system, WhatsApp usage duration, linked devices
- Queries per Hour
- Over 100 million
- Countries Affected
- 245
- Previous Warning
- Yes, in 2017