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Japan: Data Breach Incidents by Country / region

Search incidents by company, country, industry, year and attack method. Review affected data, impact, verification status, company responses and sources.

Country / region: JapanReset
767 results
CardsTable
Title / subjectOrganizationsVerificationReported impactDisclosed
Komatsu: misconfigured user directory let 139,302 registered users see each other’s data小松製作所Confirmed139,302 People2026-06-16
Mikasa: online-shop customer data may have leaked via discarded PC that re-entered circulationミカサInvestigatingUnknown2026-06-16
Saga Hirakawaya online shop: card and customer data may have leaked after intrusion佐嘉平川屋InvestigatingUnknown2026-06-15
Nagoya City: Oe JHS trip booklet loss exposed data on 126 students名古屋市Confirmed126 People2026-06-15
Sakai City: contact list for 124 school-facility committee members mis-emailed堺市Confirmed124 People2026-06-12
Kawagoe Chamber of Commerce: 4,363 member records mis-emailed externally川越商工会議所Confirmed4,363 Records2026-06-12
D&M: 633 FAX-order records may have leaked after file-server ransomwareD&MInvestigating633 Records2026-06-12
Hachioji City: childcare data for 11,997 children emailed to 22 facilities in error八王子市Confirmed11,997 People2026-06-11
Kochi University of Technology: 418 mail counterparts may have leaked after faculty laptop loss高知工科大学Investigating418 Records2026-06-09
Hokkaido Cancer Center: patient data may have leaked after improperly disposed HDDs entered circulation北海道がんセンターInvestigatingUnknown2026-06-08
Hokkaido Medical Center: patient data may have leaked after improperly disposed HDDs entered circulation北海道医療センターInvestigatingUnknown2026-06-08
Kyushu Electric TD: 13.54M customer records may be exposed after backup SSD went missing九州電力, 九州電力送配電Investigating13,540,000 Records2026-06-08
Kawasaki City: 552 emails leaked via Miyamae Sports Center lottery notices川崎市Confirmed552 People2026-06-08
Sen Corp Hai Cheese! Photo: purchaser name/address/phone leaked after intrusion千ConfirmedUnknown2026-06-05
Sumoto City: hometown-tax data posted to SNS; up to about 23,000 records may have leaked洲本市InvestigatingUnknown2026-06-05
en Japan Mid-Career: 2,503 credential-stuffing logins may have exposed member pagesエン・ジャパンInvestigating2,503 Accounts2026-06-05
Visual Arts: customer/partner personal data may have leaked after cloud-storage intrusionビジュアルアーツInvestigatingUnknown2026-06-04
JAHMC: 1,051 contacts may have been viewed after Iwate branch mailbox intrusion日本医業経営コンサルタント協会Investigating1,051 Records2026-06-04
Fujita Health University Hospital: 1,365 patient records may have leaked after nurse PC support-scam藤田医科大学病院Investigating1,365 Records2026-06-03
Woman’s Career Change type reports possible data exposure through unauthorised logins株式会社キャリアデザインセンターInvestigatingUnknown2026-05-30