ソニーネットワークコミュニケーションズ（So-net）Data breach / unauthorized access incident
- Occurred on
- October 19, 2026
- Announced on
- October 27, 2026
- Severity
- SSLarge-scale compromise of sensitive data such as payment or identity-verification records affecting millions.
- Scale
- 2,141,986 people
- Main impact
- Unauthorized access to the member database resulted in the leakage of a total of 2,141,986 records of current members and some former members, including names, phone numbers, email addresses, user IDs, dates of birth, gender, etc.; additionally, email service email addresses and passwords (equivalent to about 54,401 records), 16 bank account records, and 7 notification documents were confirmed.
- Information involved
- Email addressUser / member IDPasswordFull namePhone numberDate of birthIdentity verification data
- Cause / key point
- Data leak due to unauthorized access: an external unauthorized intrusion into the member database (unauthorized access).
- Industry
- IT & telecom
- Last updated
- November 5, 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 →