日本ネットワークセキュリティ協会（JNSA）Data breach / unauthorized access incident
- Occurred on
- October 30, 2026
- Announced on
- November 6, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 15,128 people
- Main impact
- Due to unauthorized access to 情報セキュリティ理解度チェックサービス, up to 15,128 administrator and user records may be included, and administrator emails and names, user IDs, and hashed passwords may have been leaked.
- Information involved
- Email addressHome addressFull nameUser / member IDPassword
- Cause / key point
- Unauthorized access by a third party (specific intrusion route under investigation).
- Industry
- Services & other
- Listing / capital
- Non-profit corporation
- Sources
- Last updated
- November 8, 2026
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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: Unauthorized access (method undisclosed)(Breached, but the technique was not identified or disclosed)
Read the Unauthorized access (method undisclosed) guide and national trends →