Overview
The second report says up to 2,230,812 user email addresses were included; as an upper bound the count is left blank. Per the company, this stems from unauthorised access to the Arara email-delivery platform (recorded separately); this figure is a subset of the vendor scope 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
- メール配信委託先への不正アクセスによる情報漏えいに関する件（第2報）株式会社TKC · 2026-11-09
- メール配信委託先への不正アクセスによる情報漏えいの可能性について（第1報）株式会社TKC · 2026-11-09