2025 Covenant Health — Qilin ransomware; revised impact nearly 478k patients

Covenant Health revised its May 2025 breach impact to 478,188 individuals after further data review. The organization said it learned on May 26, 2025 that an attacker had accessed systems on May 18, 2025; Qilin later claimed theft of roughly 852 GB across about 1.35 million files. Potentially exposed fields included names, addresses, dates of birth, medical record numbers, Social Security numbers, health insurance information, and treatment details such as diagnoses, treatment dates, and treatment types. Covenant Health began mailing notification letters on December 31, 2025 and offered 12 months of identity protection services.