Every public data breach

Disclosed this week47On record26,367

47 disclosed this week · 26,367 on record

Sierra Management Group

Disclosed Jun 7, 20261,279 affectedConfirmed

Official notice

What is known

People affected1,279 (as reported to HHS)
DisclosedJun 7, 2026
AttackHacking
Data exposedNamesHealth
SectorHealthcare · US
StatusConfirmed

Sources

Official noticeoag.ca.gov
California Attorney General breach notice: Sierra Management Group
Official noticeocrportal.hhs.gov
HHS OCR breach report: Sierra Management Group (Business Associate, CA)

Notices filed

TotalJun 7
HHS OCR1,279 people
Residents of CAJun 29
California AGCount not stated
History of this record
sector2026-09-25
other to healthby backfillSource
attack2026-09-25
unknown to hackingby backfillSource
data_types2026-09-25
[] to ["names","health"]by backfillSource
records_basis2026-09-25
empty to hhsby backfillSource
records2026-09-25
empty to 1279by backfillSource
disclosed2026-09-25
2026-06-29 to 2026-06-07by backfillSource
Added2026-09-25
First recordedby backfillSource

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

Everything about Sierra Management Group