Mastery Charter High School
ent_f2d6a12770f4d9263c9c3f0e
Disclosures
5
State AG · 5 jurisdictions
Multi-filing incidents
1
incidents joining 2+ filings here
Max affected reported
37,031
nationwide · State AG IN
Leak-site claims
0
none in sample
Identity resolution
- Canonical name
- Mastery Charter High School
- Normalized
- mastery charter high school— dedupe via name-norm; Microsoft / MSFT collapse to one row
- GLEIF LEI
- No match
- SEC EDGAR CIK
- None — not an SEC registrant
- Domain
- None on record
Disclosure history (5)newest first
- New Hampshire State AGas victim2025-06-12
Mastery Charter High School detected malicious encryption (ransomware) on September 15, 2024. An unauthorized actor downloaded data, including personal information (names) of five New Hampshire residents. The school shut down systems, engaged cybersecurity professionals, and notified federal law enforcement. Affected individuals are offered complimentary credit monitoring.
- Indiana State AGas victim2025-06-06
Mastery Charter High School reported a data breach to the Indiana Attorney General. The breach occurred on 2024-09-14 and was reported on 2025-06-06. 1 Indiana residents were affected. 37,031 individuals affected in total.
- Vermont State AGas victim2025-06-06
Mastery Charter High School experienced a cybersecurity incident in September 2024 involving malicious encryption attributed to an unauthorized actor. The incident resulted in data exfiltration and affected personal information including names. The school shut down systems, engaged cybersecurity professionals, reported to federal law enforcement, and offered credit monitoring to affected individuals.
- Maine State AGas victim2025-06-06
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.
- Massachusetts State AGas victim2024-12-23
Mastery Charter High School reported a data breach to the Massachusetts Office of Consumer Affairs and Business Regulation. The breach was reported on 2024-12-23. 14 Massachusetts residents were affected.