Other

Yahoo! JAPAN ID

Yahoo! JAPAN ID (run by LY Corporation) was hit in 1 recorded cybersecurity incident. The latest was disclosed on 2020-08-06.

About the service

Website

https://id.yahoo.co.jp/

Run by

LY Corporationsince 2023-10-01

Formerly run by

Yahoo Japan Corporation2019-10-01 to 2023-10-01

Category

Other

For

People

Incident history

Disclosed 2020-08-06Updated 2020-08-11 08:05Tokyo[Resolved][Severity: Critical][Breached][Critical]
Yahoo Japan: a bug in Yahoo! JAPAN ID wrote users' profile edits into up to 387,460 other people's IDs
[Misconfiguration][Data leak]Leaked 387.5KOrganizations 1

		Incident	Role	Impact level				Methods	Impacts		Status
2020-08-06	2020-08-11 08:05	Yahoo Japan: a bug in Yahoo! JAPAN ID wrote users' profile edits into up to 387,460 other people's IDs	[Breached]	[Critical]	[Critical]	1 Yahoo Japan Corporation	Tokyo	[Misconfiguration]	[Data leak]	387,460	[Resolved]

Other incidents of the operator (6)

Disclosed 2026-10-09Updated 2026-10-26 18:29Aomori, Hiroshima, Osaka, Shizuoka, Tokyo[Investigating][Severity: Critical]
Commune: unauthorized access to the Commune community platform
[Intrusion][Data leak]Leaked 307KOrganizations 12
Disclosed 2024-11-29Updated 2024-12-12 16:21Tokyo[Resolved][Severity: Critical]
LY Corp: a LINE Album defect showed thumbnails of other users' album images, affecting over 120,000 users in Japan
[Misconfiguration][Data leak]Organizations 1
Disclosed 2024-08-26Updated 2024-09-03 08:05Tokyo[Resolved][Severity: Major]
LY Corp: credential stuffing on LINE Business IDs hijacked 688 official accounts, exposing friends' chats and other data
[Credential abuse][Data leak][Fraud]Organizations 1
Disclosed 2024-08-05Updated 2024-08-14 08:05Tokyo[Resolved][Severity: Major]
LY Corp: a defect in Yahoo! JAPAN ID SMS login may have let third parties read Yahoo! Mail
[Misconfiguration][Data leak]Organizations 1
Disclosed 2024-02-14Updated 2026-10-23Tokyo[Contained][Severity: Major]
LY Corporation: contractor accounts misused; 57,611 staff-related records may have leaked
[Credential abuse][Data leak]Leaked 57.6KOrganizations 1
Disclosed 2023-11-27Updated 2024-04-23 08:05Tokyo[Contained][Severity: Critical]
LY Corporation: contractor PC malware led to access to former LINE systems, and up to about 520,000 records leaked
[Malware][Intrusion][Data leak]Leaked 519.5KOrganizations 1

		Incident				Methods	Impacts		Status
2026-10-09	2026-10-26 18:29	Commune: unauthorized access to the Commune community platform	[Critical]	12 Commune Inc., Aomori Prefectural Government, LY Corporation, Mazda Motor Corporation, Panasonic Corporation, Suzuki Motor Corporation, Yamaha Motor Co., Ltd., Bandai Namco Experience Inc., Koike-ya Inc., Morinaga Milk Industry Co., Ltd., Sansan, Inc., Yamaha Corporation	Aomori, Hiroshima, Osaka, Shizuoka, Tokyo	[Intrusion]	[Data leak]	307,000	[Investigating]
2024-11-29	2024-12-12 16:21	LY Corp: a LINE Album defect showed thumbnails of other users' album images, affecting over 120,000 users in Japan	[Critical]	1 LY Corporation	Tokyo	[Misconfiguration]	[Data leak]	Unknown	[Resolved]
2024-08-26	2024-09-03 08:05	LY Corp: credential stuffing on LINE Business IDs hijacked 688 official accounts, exposing friends' chats and other data	[Major]	1 LY Corporation	Tokyo	[Credential abuse]	[Data leak][Fraud]	Unknown	[Resolved]
2024-08-05	2024-08-14 08:05	LY Corp: a defect in Yahoo! JAPAN ID SMS login may have let third parties read Yahoo! Mail	[Major]	1 LY Corporation	Tokyo	[Misconfiguration]	[Data leak]	Unknown	[Resolved]
2024-02-14	2026-10-23	LY Corporation: contractor accounts misused; 57,611 staff-related records may have leaked	[Major]	1 LY Corporation	Tokyo	[Credential abuse]	[Data leak]	57,611	[Contained]
2023-11-27	2024-04-23 08:05	LY Corporation: contractor PC malware led to access to former LINE systems, and up to about 520,000 records leaked	[Critical]	1 LY Corporation	Tokyo	[Malware][Intrusion]	[Data leak]	519,506	[Contained]