California Health System Breach Exposes 65,000 Patients in Single Incident

City Health reported unauthorized access to electronic medical records affecting 65,000 patients on April 14, 2026, constituting 90 percent of total exposure across four healthcare breaches filed with HHS between mid-April and May 1. Three additional incidents affecting 7,768 patients occurred at University of Michigan, Iowa's health department, and a Texas pain management practice. The concentration in a single organization underscores cascade risk when large healthcare systems experience security failures.