DisclosureLens
HackingHealthcareHealthcareStolen CredentialsData ExfiltratedCustomer Data InvolvedDelayed DiscoveryPIIPHIIdentity (basic)Government IDHealth (basic)Financial accountMediumContained

Marin Cancer Care

bd_6e5505eb75f9a67c · schema v1 · pii pii-v1

Severity

Medium

Discovered

Dec 8, 2025

Filed

Apr 23, 2026

To disclose

19 weeks

Affected

Not disclosed

Linked

2 filings

Confidence

65%
Full breach record for Marin Cancer Care2 incidents on file

Marin Cancer Care notified the California Attorney General of an unauthorized access incident. The organization learned of the breach on December 8, 2025, after investigators identified unauthorized network access between November 22, 2025, and December 6, 2025. Files were copied from the network. Affected data may include names, addresses, phone numbers, email addresses, Social Security numbers, dates of birth, medical record numbers, diagnoses, treatments, and health insurance information. The company engaged third-party investigators, reviewed affected files, and is providing complimentary identity monitoring to affected individuals. No ransomware or specific threat actor was identified.

California clockDiscovered Dec 8, 2025Notified Apr 23, 2026136d CA 60-day late19 weeks discovery → filing

Incident timeline

undetected · 16 days
discovery → filing · 19 weeks / 136 days

Nov 22, 2025

Begins

Dec 8, 2025

Discovered

Apr 23, 2026

Filed

vs. sector median

+7 wks slower

This filing is one of 2 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (1) · sorted by filing gap

Filing propagation · 2 filings · 2 states

View merged incident ↗
Vermont State AGApr 23 · first
California State AGApr 23 · first · this page

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.