Confirmed

Chubu Telecommunications commufa mail: 727,176 people affected via KDDI mail platform breach

Chubu Telecommunications announced on June 23 the intrusion into the KDDI system behind commufa mail and fixed the leaked count on July 6.

Last updated: 2026-11-09

Overview

Email addresses of 727,176 people leaked, including mail passwords of 724,344 (a subset). 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

  1. Occurred
  2. Discovered
  3. 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

  1. コミュファのメールサービスに対する不正アクセスの発生について中部テレコミュニケーション株式会社 · 2026-11-09
  2. コミュファ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中部テレコミュニケーション株式会社 · 2026-11-09

Related information

kddi-isp-mail-platform-breach-2026

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