Houghton Mifflin Harcourt Company
bd_0db0c5cbadd13d1e · schema v1 · pii pii-v1
Full breach record for Houghton Mifflin Harcourt Company →Threat-actor claim — not a regulatory filing
This row is a claim by the ransomware group Shinyhunters on its public extortion blog. It has not been validated by the victim or any regulator. Treat attribution and counts as the threat actor's assertion until a regulatory filing or victim disclosure corroborates them.
Source: Ransomware.live
Post text · scraped from the leak site
HMH, or Houghton Mifflin Harcourt, is a long-established publishing company specializing in educational content. They provide a variety of instructional technology, assessments, and other learning materials to schools in over 150 countries. The company also publishes a number of well-known trade and reference works, alongside children's books. Their goal is to foster a lifelong love of learning in every individual they serve.
Source provenance
- Source URL
- https://breachforums.hn//hmhco.html
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
- Filed at
- Jul 8, 2025
- Raw hash
- bf70eaafb75ba5c4881482c28ec733325957195468cfee59915e78b43697f5fe
Reporting entity
- Name
- shinyhunters
Victim entity
- Name
- Houghton Mifflin Harcourt Companynorm: houghton mifflin harcourt
- Domain
- hmhco.com
- Industry
- Educationllm
What this source establishes
- Source ceiling
- A leak-site claim can't tell us: discovery date · materiality · notification · affected count · confirmed data types · compliance clock. These stay blank until a regulatory filing or victim disclosure lands.
- Attack vector
- Ransomware· shinyhunters
- Threat actor
- ShinyhuntersExternalFinancial
Compliance
- Compliance flags
- — (clock not assessable for this source)
Extraction provenance
- Status
- No extraction artifact recorded for this disclosure.