McLaren Health Care ransomware attack leaks data of 2.2 million
A breach that occurred in July–August 2023 at US hospital operator McLaren Health Care exposed the personal information of about 2.2 million people. The leaked information included names, Social Security numbers and sensitive medical information such as diagnoses, prescriptions and test results. McLaren Health Care sent breach notifications in November, and it also emerged that patient information had been stolen during a ransomware attack.
Key facts
- Affected organisation
- McLaren Health Care
- Incident type
- Ransomware
- Occurred / detected
- Not confirmed
- Scale of damage
- Personal and sensitive medical information of about 2.2 million people
- Cause / method
- Data theft in a ransomware attack
- Location
- United States
If your data was exposed
Exposed dataNameNational ID numberHealth & medical data
- Don’t tap links in texts, calls or emails that mention this incident and offer compensation, refunds or breach checks. Check directly on the organisation’s official website or app.
Timeline
- McLaren Health Care notified that a breach in July–August had exposed the personal and medical information of about 2.2 million people.
- It emerged that patient information had been stolen during a ransomware attack.
- The number affected was put at more than 2.3 million.
- The number affected was again put at about 2.2 million.
5 related reports
- McLaren Health Care says data breach impacted 2.2 million people
- Healthcare giant McLaren reveals data on 2.2 million patients stolen during ransomware attack
- McLaren Health Care breach exposes medical data of 2.3M+ individuals
- IOTW: McLaren Health Care data breach impacts 2.2 million people
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Other incidents at McLaren Health Care
Michigan's McLaren Health Care restores operations after cyber-attack
McLaren Health Care in Michigan was hit by a cyber-attack. It was reported on 15 May 2025 that operations had returned to normal, and the date of the attack and the extent of the damage have not been confirmed.
Related reports: 2 · last report →McLaren Health Care ransomware disrupts care, affects 740,000 people
740kImpact: 740,000 people affected; disruption of cancer treatment, cardiac testing and prescriptions
McLaren Health Care was hit by a ransomware attack in August 2024, disrupting cancer treatment, cardiac testing and prescriptions. The company's chief executive said cyber security experts were investigating the attack. About 10 months later, the company disclosed that 740,000 people had been affected.
Related reports: 4 · last report →McLaren Health Care ransomware disrupts care, data of 743,000 leaked
743kImpact: Data of about 743,000 patients leaked; disruption of care and systems
In August 2024, McLaren Health Care suffered outages of its IT and phone systems and some patient services due to a ransomware attack. Radiotherapy and stroke care resumed, and systems and operations were restored later that month. In June 2025, the company notified about 743,000 patients of the data breach.
Related reports: 16 · last report →
The summary and key facts are written by AI from related reports and may contain errors. Check the original articles and the organisation’s official statements for accurate details.