Ten breaches that shaped the conversation about data security in 2025, as compiled in the January 2026 edition of Data Gist magazine.
1. Yale New Haven Health System data breach
Date: March 2025. Impact: 5.5 million records.
2. SK Telecom breach
Date: April 2025. Impact: 27 million users.
3. Marks & Spencer ransomware attack
Date: April 2025. Impact: £300 million in losses.
4. Blue Shield of California breach
Date: April 2025. Impact: 4.7 million records.
5. The 16 billion passwords leak
Date: June 2025. Impact: 16 billion user credentials and passwords.
6. Qantas data breach
Date: June 2025. Impact: 5.7 million records.
7. TransUnion data breach
Date: July 2025. Impact: 4.4 million customer records.
8. Allianz Life breach
Date: July 2025. Impact: 2.8 million records.
9. Farmers Insurance data breach
Date: August 2025. Impact: 1.1 million records.
10. Red Hat GitLab breach
Date: October 2025. Impact: 570 GB of data from over 28,000 repositories.
