Company

Seibu Holdings Inc.

Seibu Holdings Inc. (Toshima, Tokyo; Transport and postal services) appears in 1 related cybersecurity incident. The latest was disclosed on 2026-11-02 14:00.

Profile

Industry/type

Transport and postal services

Location

Tokyo, Toshima

Services

SEIBU PRINCE CLUB

Website

https://www.seibuholdings.co.jp/

Public figures

–

Metric	Value	Scope	As of	Source
–

Incident history

Disclosed 2026-11-02 14:00Updated 2026-11-09Tokyo[Investigating][Severity: Critical][Through a supplier][Major]
WILLs: NetMile breach may expose names and email addresses of up to about 5.49 million people
[Intrusion][Data leak][Service outage]Leaked 5.5MOrganizations 2

		Incident	Role	Impact level				Methods	Impacts		Status
2026-11-02 14:00	2026-11-09	WILLs: NetMile breach may expose names and email addresses of up to about 5.49 million people	[Through a supplier]	[Major]	[Critical]	2 WILLs Inc., Seibu Holdings Inc.	Tokyo	[Intrusion]	[Data leak][Service outage]	5,490,000	[Investigating]