已確認
2rinkan confirms app API breach affecting 3,179,454 people
The June 19 final report confirmed personal-information exposure affecting 3,179,454 people. The earlier maximum of 3,455,754 is not retained as an exact total.
日本：依國家或地區查詢資料外洩事件
依企業、國家、產業、發生年份和攻擊方式查詢事件，了解外洩資料、影響範圍、查證狀態、企業應對及來源。
調查中
Tokyo Monorail: data of about 3,400 people may have leaked after loss of a desktop PC awaiting disposal
Possible data leak: A desktop PC from Haneda T2, staged for disposal in the T1 warehouse, could not be found during an April 3, 2026 disposal check; disclosed April 23.
調查中
Mazda Hospital: data of 626 patients may have leaked after imaging contractor cloud misconfiguration
Possible data leak: An imaging contractor mis-set cloud sharing so files were readable by unauthorised parties from early April 2023 to mid-December 2024; disclosed April 23, 2026.
調查中
Taisei Housy: customer data may have leaked via ielove CLOUD intrusion
After ielove’s CLOUD-intrusion disclosure and an April 20 report saying some Taisei customer data may have leaked, the firm disclosed on April 22.
調查中
Takahata Town: data of 2,354 people in the paddy-conversion system may have leaked via YCC
Possible data leak: After the April 2, 2026 attack on maintenance contractor YCC, paddy-conversion system data was found on the vendor server; disclosed April 20. Exfiltration not confirmed.
調查中
Clearth Rent: customer data may have leaked via ielove CLOUD intrusion
Possible data leak: ielove reported unauthorised access and data acquisition on April 5–6, 2026; Clearth’s April 20 notice and May 13 follow-up listed name, email, phone, address and preferences among leaked fields.
調查中
Oguni Town: 1,369 welfare-medical records may have leaked via YCC ransomware
Possible data leak: After the April 2, 2026 attack on former contractor YCC, April 2019 welfare-medical data was found on the vendor server; disclosed April 17.
調查中
Nihon Zaitaku: customer data may have leaked via ielove CLOUD intrusion
After receiving ielove’s April 16, 2026 investigation report on the April 5–6 CLOUD intrusion, Nihon Zaitaku disclosed possible customer-data leakage on April 17.
調查中
Kaneyama Town: town clinic patient data may have leaked via YCC ransomware
Possible data leak: After the April 2, 2026 YCC attack, clinic medical-admin data was found on the vendor server by April 16; disclosed April 17.
調查中
Rize Clinic: patient LINE data may have leaked after LINE-delivery-system intrusion
After suspicious LINE messages on April 9, 2026, an April 17 update said LINE display names, clinic, campaign interest and some chat history may have leaked. Chart name/phone fields are not stored in that system.
調查中
Satte City: national-health data of 34,330 people may have leaked via subcontractor YCC
Possible data leak: AGS maintained the high-cost medical-care system and subcontracted to YCC. After YCC’s April 2, 2026 attack, city data held there was found on April 8; first notice April 17 and headcount on May 25.
調查中
Yamagata Prefecture: about 26,800 entrusted records may have been exposed via YCC ransomware
Possible data leak: After the YCC file-server attack, the prefecture disclosed on April 17 that related data known as of April 16 had been stored on that server. No impact confirmed on live operational systems.
調查中
Yamagata Kotsu: bus and taxi customer data may have leaked via YCC ransomware
Possible data leak: After the April 2, 2026 YCC attack, build-contract data including ended contracts was found on the vendor server by April 16; disclosed April 17.
調查中
Nippon Rent-A-Car: car-share member data may have leaked via Nippon Telenet ransomware
Possible data leak: After Nippon Telenet (UPR subcontractor for car-share call centres) was attacked on March 9, 2026, UPR reported on April 13 and Nippon Rent-A-Car disclosed April 17. Rental-car members out of scope.
調查中
Yamako: 2,398 customer and staff records may have leaked via YCC ransomware
Possible data leak: After the April 2, 2026 YCC attack, core-system data including ended contracts was found on the vendor server by April 17.
調查中
Shonai Town: library and training-room users may have leaked via YCC ransomware
Possible data leak: After the April 2, 2026 YCC attack, build-time data from the town and its designated manager was found on the hit server by April 17.
調查中
Jusnet reports possible data leak from employee Chatwork account
Unauthorised access to an employee’s Chatwork account may have exposed names, contacts and business/service-use information. No affected-person or record total was published.
已確認
Yokosuka City: data of 145 people and 12 firms leaked via misattached tax FP-consultation list
On April 8, 2026 the tax office emailed the wrong FP-consultation list to another firm; noticed April 15 after one recipient opened then deleted it; disclosed April 16.
調查中
Yamagata City: staff and resident data may have leaked via contractor YCC ransomware
Possible data leak: After the April 2, 2026 YCC attack, a review through April 15 found city data including ended contracts still on the vendor server; disclosed April 16.
調查中
Cecile: customer data may have leaked via Nippon Telenet cyber-attack on fax-sending contractor
Fax contractor Nippon Telenet was attacked on March 9, 2026; on April 8 Cecile was told a Feb 24 fax-send backup may have been on the hit server and disclosed April 16.