イズミ（ゆめオンライン・ゆめデリバリー）Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 14, 2026
- Severity
- AFinancial and HR records — information that easily translates into monetary damage.
- Scale
- 400,000 records
- Main impact
- Following an attack on IDCFクラウド used by a contractor, up to 約40万件 of names and email addresses may have been affected. The information was encrypted, and no actual leakage or unauthorized use has been confirmed.
- Information involved
- Email addressFull name
- Cause / key point
- This incident is related to a ransomware attack on part of the IDCFクラウド systems used by the delivery contractor; it is not treated as a confirmed breach specific to イズミ.About Ransomware
- Industry
- Retail & e-commerce
- Listing / capital
- Listed company東証プライム 8273(イズミ)
- Sources
- Last updated
- October 20, 2026
Stock price reaction to the disclosureイズミ / 東証プライム 8273
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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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Same industry
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Attack method classification: Ransomware(Encrypting data and demanding a ransom)
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