Aesto LLC, operating as Aesto Health, has disclosed a major healthcare data breach affecting approximately 9.54 million individuals after an unauthorized actor compromised a portion of the company’s Amazon Web Services infrastructure. The intrusion occurred between December 2 and December 18, 2025, but was not confirmed until May 26, 2026, following an external forensic investigation and manual review. Aesto, which provides SaaS tools for migrating, archiving, and accessing electronic health record data, determined that protected health information belonging to patients of multiple healthcare clients may have been accessed or stolen. Exposed data varied by individual but included names, dates of birth, medical and health insurance information, Social Security numbers, driver’s license and other government identification numbers, taxpayer identification numbers, and financial account numbers. The incident reportedly impacts patients associated with twenty-nine (29) healthcare providers, including VillageMD, Everside Health, Marana Health, and Together Women’s Health. Aesto began notifying affected individuals on August 21, 2026, and is offering twenty-four (24) months of Experian identity theft protection and credit monitoring. At the time of this publication, no threat actor or ransomware group has publicly claimed responsibility for the breach.