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City of Hope

Disclosed Dec 12, 20232 years ago902,540 affectedConfirmed

Official notice

The covered entity (CE), City of Hope, reported that it experienced a cyber-attack that affected the protected health information (PHI) of 902,540 individuals. The PHI involved included names, dates of birth, Social Security and drivers’ license numbers, financial and health insurance information, diagnoses, and other treatment information. The CE notified HHS, affected individuals, and the media. In its mitigation efforts, the CE implemented additional administrative, technical, and security safeguards.

What is known

People affected902,540 (as reported to HHS)
DisclosedDec 12, 2023
DiscoveredOct 13, 2023
HappenedJul 7, 2023
AttackHacking
Data exposedNames, Health
SectorGovernment · US
StatusConfirmed

Sources

Source
California Attorney General breach notice: City of Hopeoag.ca.gov · Official notice
Washington Attorney General breach notice: City of Hopeatg.wa.gov · Official notice
Oregon DOJ breach notice: City of Hopejustice.oregon.gov · Official notice
Vermont Attorney General: 2024-04-02 City of Hope Data Breach Notice to Consumersago.vermont.gov · Official notice
HHS OCR breach report (archive, resolved): City of Hope (Healthcare Provider, CA)ocrportal.hhs.gov · Official notice

Notices filed

WhereFiledPeople
HHS archivetotalDec 12, 2023902,540
California AGresidents of CAApr 2, 2024
Washington AGresidents of WAApr 2, 20243,784
Vermont AGresidents of VTApr 2, 2024
Oregon DOJresidents of ORApr 3, 2024
Oregon DOJresidents of ORApr 16, 2024827,149

Other breaches at City of Hope

BreachAffected
Disclosed Aug 3, 2017Aug 3, 20179 years agoHacking3,400
Disclosed Mar 4, 2016Mar 4, 201610 years agoHacking1,024
History of this record
  • 2026-09-25 · data_types: [] to ["names","health"] · backfill source
  • 2026-09-25 · records_basis: empty to hhs · backfill source
  • 2026-09-25 · records: empty to 902540 · backfill source
  • 2026-09-25 · disclosed: 2024-04-02 to 2023-12-12 · backfill source
  • 2026-09-25 · summary: empty to The covered entity (CE), City of Hope, reported that it experienced a cyber-attack that affected the protected health information (PHI) of 902,540 individuals. The PHI involved included names, dates of birth, Social Security and drivers’ li · backfill source
  • 2026-09-25 · source: empty to https://ago.vermont.gov/document/2024-04-02-city-hope-data-breach-notice-consumers · backfill source
  • 2026-09-25 · attack: unknown to hacking · backfill source
  • 2026-09-25 · discovered: empty to 2023-10-13 · backfill source
  • 2026-09-25 · added · backfill source

First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.

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