Highmark

Disclosed Jun 24, 20215 years ago5,921 affectedConfirmed

Official notice

What is known

People affected	5,921 (as reported by the organization)
Disclosed	Jun 24, 2021
Happened	Dec 23, 2020
Attack	Not stated
Data exposed	Not stated
Sector	Healthcare · US
Status	Confirmed

Sources

Source	Kind
California Attorney General breach notice: Highmarkoag.ca.gov · Official notice	Official notice
Indiana Attorney General 2021 data breach report: Highmarkin.gov · Official notice	Official notice

Notices filed

Where	Filed	People
California AGresidents of CA	Jun 24, 2021
Indiana AGresidents of IN	Jun 30, 2021	4

Other breaches at Highmark

Breach	Disclosed	Attack	Sector	Status	Affected
Disclosed Mar 29, 2024Mar 29, 20242 years agoInsider	Mar 29, 20242 years ago	Insider	Insurance	Confirmed	6,205
Disclosed Mar 11, 2022Mar 11, 20224 years agoPhishing	Mar 11, 20224 years ago	Phishing	Healthcare	Confirmed	1.1M
Disclosed Jul 8, 2014Jul 8, 201412 years agoLost or stolen device	Jul 8, 201412 years ago	Lost or stolen device	Healthcare	Confirmed	2,589

History of this record

2026-09-25 · sector: other to health · backfill source
2026-09-25 · records_basis: empty to organization · backfill source
2026-09-25 · records: empty to 5921 · 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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