Mass General Hospital Data Breach: Health Information Exposed
By Join The Case · Published December 18, 2025 · Updated December 18, 2025 · 7 min read
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Dapeer Law, P.A., a top-rated class action law firm, is investigating the Mass General Hospital data breach. If you received notice that your information was exposed during this breach, you may be entitled to compensation. It's free to join our investigation to see if we can help you recover.

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Mass General Hospital Data Breach Lawsuit Investigation

On December 18, 2025, Mass General Hospital disclosed a privacy incident that compromised personal and insurance information for one Massachusetts patient. If you received a breach notification, you may be entitled to no-cost identity protection or financial compensation. Use the resources below to understand your rights and explore your legal options.

Download Official Breach Notice (PDF)

Key Facts of the Mass General Hospital Breach

  • Breach date: November 14, 2025
  • Discovery date: November 18, 2025
  • Consumer notifications mailed: December 10, 2025
  • Regulatory filing: Massachusetts Office of the Attorney General on December 18, 2025
  • Total individuals affected: 1 (all in Massachusetts)

What Happened

According to the hospital’s Privacy Office, insurance eligibility results for one patient were mistakenly copied and pasted into an electronic message sent to a different patient on November 14, 2025. The error was discovered four days later, and the misdirected message has since been removed from the system.

Information Exposed

The following data elements were involved:

  • Full name
  • Health insurance name
  • Coverage start date
  • Subscriber number
  • Financial account information (as listed in the state filing)

Mass General Hospital’s Response

Massachusetts General Hospital (Mass General Hospital) reported that it:

  • Removed the patient message containing the misdirected information
  • Completed an internal investigation of the incident
  • Strengthened safeguards and workforce training to prevent similar occurrences

Steps You Can Take to Protect Your Identity

The hospital’s letter outlines several free actions you can initiate immediately:

  • Place a security freeze with Equifax, Experian, and TransUnion to block new credit inquiries.
  • Set a fraud alert with one credit bureau to trigger alerts across all three agencies.
  • Review medical and financial statements for suspicious activity and report discrepancies promptly.
  • Obtain your free credit report at AnnualCreditReport.com or 877-322-8228.
  • Consult the FTC at ftc.gov/idtheft or 877-ID-THEFT for additional guidance.

Lawsuit & Claim Investigation

Even a single disclosure can create lasting privacy risks. Data breach and consumer-privacy attorneys are evaluating whether affected patients can pursue statutory damages or injunctive relief. Eligibility typically depends on receiving an official breach letter or other proof of impact.

Next step: Keep copies of your notification letter and any related expenses. If you suspect misuse of your information, document the incident and consult a qualified attorney to explore potential claims.

Company Overview

Mass General Hospital is the flagship teaching hospital of Harvard Medical School and part of the Mass General Brigham healthcare system.

Frequently Asked Questions

I received a data breach letter from Mass General Hospital — what should I do?

Follow the hospital’s recommendations: place a free security freeze, review medical and financial statements, and monitor your credit. Keep the letter for your records and consult an attorney if you wish to explore legal options.

What information did the Mass General Hospital breach expose?

The disclosure included your full name, health insurance name, coverage start date, subscriber number, and related financial account information.

Did Mass General Hospital offer credit monitoring?

The December 10, 2025 notification did not mention complimentary credit-monitoring services. Instead, it advised patients to enact free security freezes and fraud alerts on their own.

How many people were affected by the Mass General Hospital breach?

The Massachusetts filing lists one (1) affected individual.

How do I submit a claim related to the Mass General Hospital data breach?

Gather your breach notice, evidence of any fraud, and out-of-pocket expenses. Contact a data-privacy attorney to evaluate whether state or federal laws allow you to seek monetary relief.

How can I get the official breach notice (PDF) for Mass General Hospital?

You can download it directly from the Massachusetts Attorney General’s website using the button near the top of this article or via this link.

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