Data breach at medical billing firm MCBS affects 1.26 million people

Healthcare billing firm Medical Computer Business Services (MCBS) disclosed a 2025 network breach that exposed the personal and medical data of roughly 1.26 million individuals; the PEAR ransomware group claims to have exfiltrated 3.3 TB of data and has leaked it online. Exposed fields reportedly include full names, addresses, Social Security numbers, dates of birth, insurance identifiers, medical history and treatment/diagnosis information; the company named several healthcare clients as affected and advised credit monitoring and fraud alerts.