Massive Cyberattack Exposes Data of Up to 15 Million French Patients

A significant cyberattack targeting Cegedim Santé’s medical software, “Mon logiciel médical” (MLM), has compromised the personal data of an estimated 11 to 15 million French patients. The breach, discovered in late 2025, has prompted investigations and responses from both the French government and Cegedim Santé [France in English].

What Happened?

Cegedim Santé, a French software company providing solutions for the healthcare industry, confirmed the unauthorized access to patients’ personal administrative information. The compromised data includes names, birth dates, phone numbers, and postal addresses [TechRadar Pro]. Approximately 3,800 healthcare professionals across France utilize the MLM software, and around 1,500 were affected by the attack [France in English].

What Data Was Compromised?

While structured medical records remained secure, a limited amount of sensitive information was also exposed. This includes doctor’s annotations, and in some cases, details regarding patients’ sexual orientation and health conditions [France in English]. An online data sample revealed administrative information on nearly 300,000 patients, with a small fraction containing this sensitive data. Approximately 165,000 files contained doctors’ notes, with some including details on conditions like HIV/AIDS [The Register].

Company and Government Response

Cegedim Santé stated that it took immediate action upon detecting “abnormal application request behavior” and contained the incident [TechRadar Pro]. The company has notified the CNIL (Commission Nationale de l’Informatique et des Libertés), the French data protection authority, and filed a complaint with the public prosecutor. The Ministry of Health is monitoring the situation and has requested a report from Cegedim Santé [France in English].

Investigation and Scope

Estimates of the number of affected individuals vary, with France 2 reporting between 11 and 15 million patients, while a hacker claims access to data on 19 million people [France in English]. The attack targeted Cegedim’s MonLogicielMedical (MLM) software, a web-based application used by healthcare professionals for administrative and clinical tasks [TechRadar Pro].

Looking Ahead

This cyberattack underscores the growing threat to healthcare data and the importance of robust cybersecurity measures. As investigations continue, further details regarding the attack vector and the full extent of the data compromise are expected to emerge. The incident highlights the need for healthcare providers and software vendors to prioritize data protection and implement stringent security protocols to safeguard sensitive patient information.