2026 JR East — IDCF Cloud ransomware fallout; ~6.09M Viewcard/Eki-net/Club accounts
Data compromised
~4.03M Viewcard VIEW’s NET emails; ~1.67M Eki-net emails/logs; ~390k Otona no Kyujitsu Club emails + card expiry + birthdays. Names, addresses, phones, full card numbers not leaked per JR East.
Technical writeup
Verified JR East / Viewcard disclosures Oct 9, 2026 (Kyodo / Mainichi) — About 6.09 million customer accounts may have been compromised after ransomware hit SoftBank’s IDC Frontier IDCF Cloud (Oct 7). Breakdown: ~4.03M Viewcard VIEW’s NET email addresses; ~1.67M Eki-net (Shinkansen/express reservations) emails and email logs; ~390k Otona no Kyujitsu Club members’ emails, credit-card expiration dates, and birthdays. JR East states names, addresses, telephone numbers, and full credit-card numbers were not leaked. Related catalog row: idc-frontier-idcf2026.
Root cause
Customer data hosted on SoftBank subsidiary IDC Frontier IDCF Cloud East Japan Region 1 impacted by Oct 7 ransomware