> JapanHacked_Cybersecurity incidents in Japan

Company

The Mainichi Newspapers Co., Ltd.

The Mainichi Newspapers Co., Ltd. (Chiyoda, Tokyo; Information and communications) appears in 1 related cybersecurity incident. The latest was disclosed on 2026-10-19.

Profile

Industry/type: Information and communications
Location: Tokyo, Chiyoda
Website: https://www.mainichi.co.jp/

Public figures

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Metric	Value		As of	Source
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Incident history

Disclosed 2026-10-19Updated 2026-10-27 17:02Aichi, Fukuoka, Osaka, Saitama, Tokyo[Investigating][Severity: Critical][Through a supplier][Major]
Ymirlink: unauthorized access to the Cuenote FC email delivery service
[Web app exploit][Data leak]Leaked 51.6MOrganizations 15

		Incident	Role	Impact level				Methods	Impacts		Status
2026-10-19	2026-10-27 17:02	Ymirlink: unauthorized access to the Cuenote FC email delivery service	[Through a supplier]	[Major]	[Critical]	15 Central Japan Railway Company, Kyushu Railway Company, West Japan Railway Company, Ymirlink, Inc., Dai Nippon Printing Co., Ltd., Nomura Securities Co., Ltd., istyle Inc., NTTPC Communications, Inc., The Asahi Shimbun Company, Cybozu, Inc., Kansai Mirai Bank, Limited, The Mainichi Newspapers Co., Ltd., Resona Bank, Limited, Saitama Resona Bank, Limited, ValueCommerce Co., Ltd.	Aichi, Fukuoka, Osaka, Saitama, Tokyo	[Web app exploit]	[Data leak]	51,628,280	[Investigating]