DisclosureLens
HackingEducationEducationCustomer Data InvolvedPIIIdentity (basic)MediumContained

Mastery Charter High School

bd_d445c07723535b6b · schema v1 · pii pii-v1

Severity

Medium

Discovered

Sep 15, 2024

Filed

Jun 6, 2025

To disclose

38 weeks

Affected · nationwide

37,0314 in this filing

Linked

4 filings

Confidence

65%
Full breach record for Mastery Charter High School →2 incidents on file

Mastery Charter High School, an education entity based in Philadelphia, PA, reported an external system breach (hacking) occurring between September 14 and 16, 2025. The incident affected a total of 37,031 individuals, including 4 Maine residents. The breach was discovered on September 15, 2024. The entity provided written notification to affected individuals on June 6, 2025, and offered 12 months of Experian IdentityWorks identity monitoring and restoration services.

Maine clockDiscovered Sep 15, 2024 → Filed with AG Jun 6, 2025264d ✗ ME AG >90d38 weeks discovery → filing
⚠ AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline — partial

? — ?

Breach window unknown

Jun 6, 2025

Filed

—

Corroborated · see linked filings

Compliance clocks stay unassessable until a regulatory filing lands. Dashed segments fill in automatically when corroboration arrives.

This filing is one of 4 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (3) · sorted by filing gap

Filing propagation · 4 filings · 4 states

View merged incident ↗
Indiana State AGJun 6 · first
Vermont State AGJun 6 · first
Maine State AGJun 6 · first · this page
New Hampshire State AG+6d

Pattern: first filing Jun 6 (IN), last Jun 12 (NH) — a 6-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

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.