Overview
Email addresses of 1,250,543 people leaked; the company says no passwords themselves leaked. This stems from the intrusion into KDDI's mail platform for ISPs (recorded separately); the figure is a subset of KDDI's total and must not be added to it.
Timeline
- Occurred
- Discovered
- Disclosed
Organization response
Per the notice, the organisation investigated and contained the incident, notified individuals and offered monitoring or protective resources.
What you can do
Be wary of emails, SMS or calls impersonating the organisation; do not open links or attachments or enter passwords or card details. Change reused passwords on other services.
Sources
- CPIのメールサービスに対する不正アクセスについてのお詫びとご報告株式会社KDDIウェブコミュニケーションズ · 2026-11-09
- 弊社メールサービスに対する不正アクセス発生とお詫び株式会社KDDIウェブコミュニケーションズ · 2026-11-09