MCBS
Disclosed Jun 26, 20263 months ago1,261,464 affectedConfirmed
What is known
| People affected | 1,261,464 (as reported to HHS) |
|---|---|
| Disclosed | Jun 26, 2026 |
| Discovered | May 28, 2026 |
| Happened | Sep 22, 2025 |
| Attack | Hacking |
| Data exposed | Names, Health, Social Security numbers, Insurance, Dates of birth, Addresses |
| Sector | Healthcare · US |
| Status | Confirmed |
Sources
| Source | |
|---|---|
| California Attorney General breach notice: MCBSoag.ca.gov · Official notice | Official notice |
| HHS OCR breach report: MCBS (Business Associate, GA)ocrportal.hhs.gov · Official notice | Official notice |
| Texas Attorney General data security breach report BR-0005146: MCBSoag.my.site.com · Official notice | Official notice |
Notices filed
| Where | Filed | People |
|---|---|---|
| California AGresidents of CA | Jun 26 | |
| HHS OCRtotal | Jun 26 | 1,261,464 |
| Texas AGresidents of TX | Jun 30 | 13,302 |
History of this record
- 2026-09-25 · data_types: ["names","health"] to ["names","health","ssn","insurance","dob","addresses"] · backfill source
- 2026-09-25 · discovered: empty to 2026-05-28 · backfill source
- 2026-09-25 · sector: other to health · backfill source
- 2026-09-25 · attack: unknown to hacking · backfill source
- 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 1261464 · 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.