良品計画（無印良品）Data breach / unauthorized access incident
- Occurred on
- January 2, 2020
- Announced on
- November 9, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 440,000 people
- Main impact
- 無印良品's e-commerce site postponed its reopening, and it announced that the names and postal codes of approximately 440,000 customers who were cash-on-delivery recipients between 2020/01/02 and 2025/02/10 may have been accessed by unauthorized parties. The company also previously disclosed the possibility that up to about 27,260,000 customer records from the MUJIアプリ were leaked.
- Information involved
- Full nameHome addressEmail addressDate of birth
- Cause / key point
- Possible unauthorized logins by third parties via a "list-type" attack using authentication credentials obtained from other services.About Abuse of credentials
- Industry
- Retail & e-commerce
- Listing / capital
- Listed company7453
- Sources
- Last updated
- November 10, 2026
Stock price reaction to the disclosure良品計画（無印良品） 7453
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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: Abuse of credentials(Logging in legitimately with leaked or guessed passwords)
Read the Abuse of credentials guide and national trends →