ヤマハ（ヤマハネットワークエンジニア会）Data breach / unauthorized access incident
- Occurred on
- October 6, 2026
- Announced on
- October 9, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 1,600 people
- Main impact
- About 1,600 people’s email addresses, display names, self-introductions, affiliated groups, etc. were disclosed, according to the announcement. Intrusion into ヤマハ’s own systems has not been confirmed.
- Information involved
- Email addressUser / member ID
- Cause / key point
- Unauthorized access to contractor Commune.About Supply chain attacks (via vendors & shared services)
- Industry
- IT & telecom
- Listing / capital
- Listed company東証プライム 7951(ヤマハ)
- Last updated
- October 20, 2026
Stock price reaction to the disclosureヤマハ / 東証プライム 7951
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Written & reviewed
Reviewed byYutaro SasaoFounder & CEO, MediaLeap Inc.
CEO of MediaLeap Inc. Working on both sides of web advertising and web media since 2013; founded the company in May 2025.
Review scope: cross-checking against primary sources (official and government announcements), verifying claims stay within the facts, and checking source attribution。Last reviewed:
Written by:Leak Watch editorial team (AI-assisted drafts verified against sources by the editorial team) · Reviewer profile · Request a correction
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Attack method classification: Supply chain attacks (via vendors & shared services)(Compromising the provider instead of the user)
Read the Supply chain attacks (via vendors & shared services) guide and national trends →