16TB of MongoDB Database Exposes 4.3 Billion Lead Gen Records

Cybersecurity researchers discovered an unsecured 16TB database exposing 4.3 billion professional records, including names, emails, and LinkedIn data. Learn what happened, why this massive data leak enables new scams, and how to protect your PII.

In a major event that should make every professional pause and worry about their online privacy, cybersecurity researcher Bob Diachenko, working with nexos.ai, recently discovered an unprotected MongoDB database on November 23, 2025. This enormous collection, totalling around 16 terabytes (TB) of data, was left wide open online, shockingly exposing 4.3 billion professional records that criminals could easily use for targeted attacks.

For your information, MongoDB is a popular type of database widely used by businesses to store large amounts of data. According to Diachenko, the database was secured just two days later after they alerted the owner, but it is impossible to know who might have accessed it beforehand.

The Discovery ...