Large-scale incident Any 2026-11-09 Osaka after-school room: support scam makes data for 415 children, parents and staff accessible (2) 2026-11-08 teket: member data leak confirmed; all electronic-ticket services suspended (31) 2026-11-05 Morinaga Milk: group company website breached; 18 sites of 17 companies on the same server closed (17) 2026-11-05 SMBC Consumer Finance: guarantee system breach leaks income and licence numbers of up to 320,000 people (29) 2026-11-02 Prestige Core Solution: up to about 5.5 million records stolen, including three full card numbers (21) 2026-10-30 Securitize Japan: platform breach leaks investor data, including up to 9,086 Marui applicants (13) 2026-10-29 Arara: 81,329,467 email addresses leaked or at risk, affecting up to about 380 clients (308) 2026-10-26 palan: intrusion through a data-analysis tool leaks data on up to 33,348 users, campaign participants and inquirers (12) 2026-10-21 RAKUS Light Cloud: blastmail intrusion leaks customer mailing data and suspends service (58) 2026-10-21 php2shell: critical flaws in PHP (609) 2026-10-19 Ymirlink: Cuenote FC mail system intrusion (33) 2026-10-16 Studio: website builder cloud intrusion puts company and public-sector form submissions at risk (84) 2026-10-13 Arcadia: SpeeCAN RAIDEN intrusion disrupts safety alerts and puts registration data at risk (37) 2026-10-08 Commune: Commune intrusion (28) 2026-10-07 IDC Frontier: ransomware attack on IDCF Cloud (13) 2026-09-09 ApplyNow: unauthorized access to its recruiting platform (23) 2024-05-29 Iseto: ransomware leaks client organization data (13) 2022-12-23 Fujitsu: FENICS network attack affects TKC mail (11) 2022-08-04 Showcase: form service tampering may have leaked card data from Idemitsu Credit and other customer sites (10) 2021-09-16 GR: Omni EC system intrusion leaks member and reservation data of ten retailers (11) 2021-08-20 Oriental Consultants group: ransomware on business servers (10) 2021-03-02 Landbrain: ransomware on its servers (11)
Prefecture Any Aichi Akita Aomori Chiba Ehime Fukui Fukuoka Fukushima Gifu Gunma Hiroshima Hokkaido Hyogo Ibaraki Ishikawa Iwate Kagawa Kagoshima Kanagawa Kochi Kumamoto Kyoto Mie Miyagi Miyazaki Nagano Nagasaki Nara Niigata Oita Okayama Okinawa Osaka Saga Saitama Shiga Shimane Shizuoka Tochigi Tokushima Tokyo Tottori Toyama Wakayama Yamagata Yamaguchi Yamanashi
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Industry/type Any Agriculture and forestry (2) Mining and quarrying (1) Construction (22) Manufacturing (334) Electricity, gas, heat and water (37) Information and communications (500) Transport and postal services (85) Wholesale and retail trade (400) Finance and insurance (245) Real estate and rental (52) Scientific research, professional and technical services (70) Accommodation, food and drink (64) Personal services and entertainment (83) Education and learning support (158) Medical care and welfare (62) Compound services (2) Other services (131) National government (23) Prefecture (47) Municipality (396) Police (17) Public agency or corporation (33)
Organization kind Any Company Government Hospital Education Nonprofit
Employees Any Under 100 100–999 1,000–9,999 10,000 or more
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