Healthcare Data Breach Disclosures and Legal Fallout
French healthcare software provider Cegedim Santé confirmed a major breach affecting its MonLogicielMedical (MLM) product after unusual activity was detected in late 2025. The incident exposed administrative data tied to roughly 1,500 doctors (out of ~3,800 users) and patient data at large scale—reported as 15.8 million records, including 165,000 files that may contain doctors’ notes; while structured medical records were reported as intact, some administrative comments may include sensitive clinical notes and highly sensitive details (e.g., HIV/AIDS status or sexual orientation). Cegedim Santé reported notifying French authorities including CNIL and filing a complaint.
In the US, Cornerstone Specialty Hospitals agreed to a $2.35M class-action settlement tied to a December 2023 network intrusion that ultimately affected 484,957 individuals, with potentially exposed data spanning identifiers (including SSNs and government IDs), financial data, credentials, and health/insurance information; the suit also alleged delayed notification (letters mailed around July 2024). Separately, PIH Health began notifying patients about a December 2024 ransomware attack that disrupted multiple hospitals and services; investigators concluded the attacker had network access from Nov 14–Dec 23, 2024, and after a prolonged review PIH Health confirmed in Dec 2025 that patient information was present in files on compromised systems and may have been accessed or acquired, with notification letters prepared by Feb 25, 2026 amid claims of large-scale data theft and some data leakage online.

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How this story unfolded
9 events from the most recent confirmed update back to the earliest known activity.
Cornerstone agrees to $2.35 million breach settlement
Cornerstone Healthcare Group Management Services agreed to a $2.35 million settlement to resolve class action litigation over the December 2023 cyberattack and data breach. The settlement provides funds for legal fees, reimbursement of losses, credit monitoring for some class members, and pro rata cash payments.
PIH Health begins notifying patients about 2024 breach
In early 2026, PIH Health began notifying patients that personal and medical information was exposed in the 2024 ransomware attack. The provider said exposed data varied by individual and included PII and PHI, and it offered credit monitoring and identity theft protection.
Cegedim Santé notifies CNIL and files complaint
Following discovery of the breach, Cegedim Santé notified French authorities including the CNIL and filed a complaint. Reports said some exposed data may have included highly sensitive personal details and doctors' notes.
Cegedim Santé detects unusual activity and confirms data exfiltration
Cegedim Santé detected unusual activity in late 2025 and confirmed a major cyberattack affecting its MonLogicielMedical product. The breach involved exfiltration of administrative and patient data tied to roughly 1,500 doctors and 15.8 million records.
PIH Health unauthorized access period ends
PIH Health said its investigation found the threat actor's access to compromised systems lasted until December 23, 2024. Later review determined patient information was present in affected files and may have been accessed or acquired.
PIH Health detects ransomware attack and service disruption
PIH Health detected a ransomware attack on December 1, 2024, which disrupted multiple hospitals and care services. Attackers later claimed to have exfiltrated about 2 TB of data and 17 million patient records and issued a ransom demand.
PIH Health attackers gain access to network
A forensic investigation later determined that the threat actor had access to PIH Health's network beginning on November 14, 2024. This marked the start of the ransomware-related compromise affecting the California healthcare provider.
Cornerstone mails breach notifications to affected individuals
Cornerstone mailed notices to affected individuals around July 1, 2024 regarding the December 2023 cyberattack and data breach. The later lawsuit alleged the company delayed notification.
Cornerstone network allegedly accessed in cyberattack
Cornerstone Specialty Hospitals' network was allegedly accessed by a threat actor around December 19, 2023, beginning the incident that later led to a data breach lawsuit. The attacker potentially accessed and copied patient and personal information.
Related entities
Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.
Sources
4 references tracked. Mallory keeps watching after this page renders.
teiss - News - PIH Health begins notifying patients after 2024 ransomware attack exposed sensitive data
teiss.co.uk
Open sourceFrench healthcare software provider Cegedim Santé suffers major data breach | brief | SC Media
scworld.com
Open source$2.35 Million Settlement Agreed to Resolve Cornerstone Specialty Hospitals Data Breach Lawsuit
hipaajournal.com
Open sourcePIH Health Notifies Patients About 2024 Hacking Incident
hipaajournal.com
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