戸田建設（支払い管理システム等）Data breach / unauthorized access incident
- Occurred on
- October 1, 2026
- Announced on
- October 7, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 4,778 people
- Main impact
- Up to 7,200 client emails and up to 6,000 transaction records, and personal data of 4,778 employees including names, addresses, contact details, and affiliations have been confirmed leaked. Operational information leakage and impacts on clients are a concern.
- Information involved
- Email addressPhone numberHome addressFull name
- Cause / key point
- Unauthorized access to payment management systems and related systems (the intrusion route is under investigation).
- Industry
- Real estate
- Listing / capital
- Listed company東証プライム 1860(戸田建設)
- Last updated
- October 20, 2026
Stock price reaction to the disclosure戸田建設 / 東証プライム 1860
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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 →