Sierra Vista Hospital & Clinics suffered a major data breach after detecting suspicious network activity on January 29, 2025. An investigation confirmed that cybercriminals accessed and exfiltrated sensitive patient files between January 14–31, 2025, exposing personally identifiable information (PII) and protected health information (PHI). Compromised data included names, addresses, Social Security numbers, dates of birth, medical records, health insurance details, and other medical information. The breach was disclosed to regulatory authorities (Texas and Massachusetts Attorney Generals) on October 7, 2025, with notifications sent to affected patients—estimated to be thousands of current and former individuals. The exposure of such sensitive data heightens risks of fraud, identity theft, and financial exploitation. In response, the hospital secured its network, engaged external cybersecurity experts, and offered free credit monitoring (Experian IdentityWorks) to victims. The incident underscores severe vulnerabilities in healthcare cybersecurity, with potential long-term repercussions for patient trust and operational integrity.