nimocaData breach / unauthorized access incident
- Occurred on
- October 4, 2026
- Announced on
- October 6, 2026
- Severity
- CLimited data such as email addresses and identifiers.
- Scale
- 521 records
- Main impact
- Confirmed leakage of 521 card numbers, dates of birth, and email addresses; no leakage of usage history or names has been confirmed.
- Information involved
- Email addressDate of birth
- Cause / key point
- Cause under investigation.
- Industry
- Transport & travel
- Listing / capital
- UnlistedParent company: 西日本鉄道(東証プライム 9031)
ニモカ is a subsidiary of 西日本鉄道.
- Last updated
- October 20, 2026
Stock price reaction to the disclosure西日本鉄道・親会社 / 東証プライム 9031
Stock information is reference data based on Yahoo Finance and may be delayed. This site does not solicit or advise investment and does not guarantee the accuracy or completeness of this information. We accept no liability for any investment decision based on it.
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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: Under investigation / not stated(Cause not disclosed)
Read the Under investigation / not stated guide and national trends →