Every public data breach

44 disclosed this week · 26,355 on record

Memorial Sloan Kettering Cancer Center

Disclosed Sep 14, 202073,536 affectedConfirmed

Official notice

The covered entity (CE), Memorial Sloan Kettering Cancer Center, reported that employees of its business associate misconfigured a server and exposed the protected health information (PHI) of 18,913 individuals. The PHI involved included names, Social Security numbers, dates of birth, addresses, financial information, diagnoses, lab results, medications prescribed, and other treatment information. The CE notified HHS, affected individuals, the media, and provided substitute notice. In response to the breach, the CE provided free credit monitoring and fraud protection services, sanctioned workforce members responsible for the breach, and took the affected network server offline.

What is known

People affected73,536 (as reported to HHS)
DisclosedSep 14, 2020
AttackInsider
Data exposedNamesHealth
SectorHealthcare · US
StatusConfirmed

Sources

Notices filed

Other breaches at Memorial Sloan Kettering Cancer Center

History of this record
records2026-09-25
18913 to 73536by backfillSource
disclosed2026-09-25
2021-03-31 to 2020-09-14by backfillSource
Added2026-09-25
First recordedby backfillSource

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

Everything about Memorial Sloan Kettering Cancer Center