Yale New Haven Health (YNHHS), Connecticut’s largest healthcare provider, has confirmed that a recent cyberattack resulted in a data breach affecting over 5.5 million patients. Though the attack, which occurred on March 8, 2025, did not disrupt patient care, it led to the unauthorized access of sensitive personal information, including names, contact details, Social Security numbers, and demographic data. Importantly, the breach did not involve financial records, medical histories, or treatment details.

Following the incident, YNHHS notified federal authorities. On April 11, the organization publicly acknowledged the breach, and by April 14 began notifying affected individuals and offering complimentary credit monitoring and identity protection services to those whose SSNs were compromised.

With class action lawsuits already underway, this incident is a stark reminder of how costly and damaging insufficient cybersecurity can be - particularly in the healthcare sector, where patient trust and privacy are paramount. The attackers behind the breach have yet to be identified. Read more about this story on our LinkedIn page