HHS OCR report ยท 2023
The University of Massachusetts Chan Medical School data breach
OCR report facts
- Covered entity
- The University of Massachusetts Chan Medical School
- Entity type
- Business Associate
- State
- Massachusetts
- Individuals affected
- 135,394
- Submission date
- Aug 21, 2023
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Network Server
- Business associate present
- Yes
- Status
- Archive (closed)
OCR description
The covered entity (CE), The University of Massachusetts Chan Medical School, reported that it was the subject of a cyber-attack that affected the protected health information (PHI) of 135,974 individuals. The PHI involved included names, dates of births, addresses, Social Security numbers, diagnoses, medications, financial and claims information, and other treatment information. The CE notified HHS, affected individuals, the media, and provided substitute notice. In response to the breach, t...
Text as published on the HHS OCR breach portal.
Frequently asked questions
How many people were affected by the The University of Massachusetts Chan Medical School data breach?
The report to HHS OCR lists 135,394 individuals affected.
When was it reported to HHS?
It was submitted to HHS OCR on Aug 21, 2023.
What type of breach was it?
The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Network Server.
Is the investigation still open?
No. The report is in the OCR portal archive, which holds reports where OCR has closed its review.
Is a breach notice letter from The University of Massachusetts Chan Medical School legitimate?
This site cannot verify letters. Check the sender against the organisation's official website and the HHS OCR breach portal, and avoid calling numbers or clicking links only listed in an unexpected message. See our guide on what to do after a data breach notice.
Source: HHS OCR Breach Portal, OCR export October 2026. Network USA is not affiliated with HHS or The University of Massachusetts Chan Medical School.