Top 3 Largest Data Breaches by Records Exposed

The largest data breaches by records exposed include the Chinese Surveillance Network breach (4 billion records in June 2025), the 2013 Yahoo data breach (3 billion records), and the National Public Data breach (2.9 billion records).

The top 3

  1. World's Largest Data Leak: The 26 Billion Record "MOAB": The 'Mother of All Breaches' (MOAB), discovered in 2024, is the largest aggregate data leak ever, compiling 26 billion records from thousands of previous breaches, rather than a single hack on one entity.
  2. Yahoo's Record: The 3 Billion Account Breach: Yahoo's 2013 data breach remains the largest single-organization breach, compromising all 3 billion user accounts. Initial reports in 2016 and 2017 underestimated the scale, which included names, email addresses, and security questions. Yahoo
  3. Accidental Exposure: Cam4's 10 Billion Record Leak: In 2020, adult streaming site Cam4 experienced an estimated 10.88 billion log rows exposed due to a misconfigured Elasticsearch cluster left without authentication, including names, email addresses, and private chat logs. Cam4

Sources

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