Reported U.S. health-data breach
Were you affected by the Onsite Mammography data breach?
Onsite Mammography reported a breach (hacking/it incident) affecting 357,265 people. If you were a patient or member, your information may have been involved. This is not confirmed for you.
- Reported
- 2025
- People affected
- 357,265
- Organization
- Business Associate
- How
- Hacking/IT Incident
- Where
- State
- MA
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Breach data from Have I Been Pwned, used under CC BY 4.0. Awareness data from the HHS Office for Civil Rights breach portal.
About the Onsite Mammography breach
Was I affected by the Onsite Mammography breach?
Onsite Mammography reported this breach to the U.S. government, but only the organization knows exactly who was included, so it cannot be confirmed for you here. If you were a patient or member, your information may have been involved. To check whether your email appears in known breaches, run the free check below; your email never leaves your device.
What happened in the Onsite Mammography breach?
Onsite Mammography reported a breach (hacking/it incident) affecting 357,265 people. If you were a patient or member, your information may have been involved. This is not confirmed for you.
How many people did the Onsite Mammography breach affect?
357,265 individuals, according to the report Onsite Mammography filed with the U.S. Department of Health and Human Services in 2025.
What should I do if I was affected?
Change any reused passwords and turn on two-factor authentication, be wary of phishing that references real details about you, and keep your own copy of your medical records so you stay in control of them going forward.