MrMaxData breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 6, 2026
- Severity
- SCompromise of deep personal data or usable credentials.
- Scale
- 1,735,154 people
- Main impact
- A leak affecting up to approximately 1.74 million people’s names, email addresses, phone numbers, and membership IDs was confirmed. Passwords, addresses, and purchase history are reported not to be affected.
- Information involved
- Email addressUser / member IDPhone numberFull name
- Cause / key point
- Server intrusion via abuse of a software feature.
- Industry
- Retail & e-commerce
- Listing / capital
- UnlistedParent company: MrMaxHD(東証プライム 8203)
MrMax is a subsidiary of MrMaxHD.
- Last updated
- October 20, 2026
Stock price reaction to the disclosureMrMaxHD・親会社 / 東証プライム 8203
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.
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: Under investigation / not stated(Cause not disclosed)
Read the Under investigation / not stated guide and national trends →