ホワイトエッセンス（予約・基幹システム）Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 5, 2026
- Severity
- SCompromise of deep personal data or usable credentials.
- Scale
- 1,050,000 accounts
- Main impact
- Confirmed leakage of registration data for approximately 1,050,000 accounts, containing all or part of items such as name, contact information, date of birth, login ID, and encrypted password. There is a risk of misuse.
- Information involved
- Email addressUser / member IDPasswordPhone numberHome addressFull nameDate of birth
- Cause / key point
- Unauthorized access to the core system exploiting a vulnerability in the reservation site's program.About Exploitation of vulnerabilities
- Industry
- IT & telecom
- Listing / capital
- Unlisted
- Sources
- Last updated
- October 20, 2026
Is this incident worth paying attention to?
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: Exploitation of vulnerabilities(Breaking in through holes in software and devices)
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