アイスタイル（@cosme）Data breach / unauthorized access incident
- Occurred on
- October 28, 2026
- Announced on
- November 2, 2026
- Severity
- SSLarge-scale compromise of sensitive data such as payment or identity-verification records affecting millions.
- Scale
- 3,000,000 people
- Main impact
- Approximately 3,000,000 members' information was leaked due to unauthorized access by a third party. It includes names, addresses, phone numbers, email addresses, dates of birth, and attribute data such as skin and hair types, but is said not to include login passwords or credit card information.
- Information involved
- Full nameHome addressPhone numberEmail addressUser / member IDDate of birth
- Cause / key point
- Member information was leaked externally due to unauthorized access by a third party; the specific method is unknown and is under investigation.
- Industry
- Retail & e-commerce
- Last updated
- November 3, 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 →