McLaren Health Care security incident history
Hacking, data breaches and other security incidents involving McLaren Health Care, with related coverage.
Michigan's McLaren Health Care restores operations after cyberattack
McLaren Health Care in Michigan was hit by a cyberattack. It was reported on May 15, 2025, that operations had returned to normal, and the date of the attack and the scale 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 CEO said cybersecurity 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. Radiation therapy 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 →McLaren Health Care ransomware attack leaks data of 2.2 million
2.2MImpact: Personal and sensitive medical information of about 2.2 million people
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.
Related reports: 5 · last report →