CYBER ATTACKS IN JAPAN.
LATEST NEWS

Cyber attacks in Japan each day

Latest cyber attacks in Japan

• Satofuru: Satofuru data leak: donors to Sanjo City not affectedData breach · Other · 4 reports · 30 Oct 2026, 14:30 UTC
• All Nippon Airways: ANA personal data leak affects 37,800 people including passport numbers; Muji may have lost 27.26 million records, including data of former membersData breach · Transport · 10 reports · 30 Oct 2026, 14:24 UTC
• Nihon Kotsu: Nihon Kotsu may have leaked data on 290,000 peopleData breach · Transport · 5 reports · 30 Oct 2026, 14:01 UTC
• Mount Fuji Yoshida Trail reservation system: Possible information leak from Mount Fuji Yoshida route passage reservation systemData breach · Government · 1 report · 30 Oct 2026, 13:02 UTC
• World: World subsidiary may have leaked personal data, about 1.2 million recordsData breach · Retail · 3 reports · 30 Oct 2026, 12:40 UTC
• Kumamoto City: Personal data of Kumamoto city event participants leaked in unauthorised access; no secondary harm confirmedData breach · Government · 5 reports · 30 Oct 2026, 12:15 UTC
• Saga University: Saga University hit by ransomware attack; personal data of 80,000 students and staff, and hospital patient information, may have leakedRansomware · Education · 16 reports · 30 Oct 2026, 12:08 UTC
• Japan Ministry of Foreign Affairs: Foreign ministry: unauthorised access may have leaked personal data of about 3,600 people, including names; no diplomatic secrets includedData breach · Government · 25 reports · 30 Oct 2026, 11:56 UTC
• Lifenet Insurance: KDDI customer information possibly leaked through unauthorised access to LifenetData breach · Finance · 1 report · 30 Oct 2026, 11:38 UTC
• World Co.: Unauthorised access at World Group subsidiary may have leaked personal data of about 1.2 million people, Hyogo PrefectureData breach · Retail · 1 report · 30 Oct 2026, 11:37 UTC
• Akita Prefecture: Successive unauthorised access leads to personal data leaks; Governor Suzuki says efforts should focus on preventing further damage (Akita)Data breach · Government · 2 reports · 30 Oct 2026, 11:30 UTC
• Keio: Japan's Keio Corporation delays interim earnings to early December after cyberattackOther attack · Transport · 13 reports · 30 Oct 2026, 11:26 UTC
• KDDI: KDDI may have leaked customer data of up to 22,541 people via unauthorised access to Lifenet Life InsuranceData breach · Technology · 13 reports · 30 Oct 2026, 11:26 UTC
• Matsuya: Beef bowl chain Matsuya leaks personal data of about 2.38 million people via unauthorised access to official app management systemData breach · Retail · 8 reports · 30 Oct 2026, 11:12 UTC
• Muji: Muji may have leaked member informationData breach · Retail · 26 reports · 30 Oct 2026, 11:01 UTC
• Yakult Honsha: Yakult Honsha reports leak of 40,000 items of informationData breach · Other · 2 reports · 30 Oct 2026, 11:01 UTC
• GMO Internet Group: GMO bounty scheme passes 400 tip-offs in three days, used to identify cyber attack perpetratorsOther attack · Technology · 93 reports · 30 Oct 2026, 10:35 UTC
• Fukushima Prefectural Police: Amid a string of corporate data leaks, Fukushima's "Police Mail Fukushima" service shut down over concerns about unauthorised accessOther attack · Government · 1 report · 30 Oct 2026, 09:35 UTC
• Sony So-net: Sony internet provider So-net hit in major data breachData breach · Technology · 16 reports · 30 Oct 2026, 09:33 UTC
• Daiwa Securities Group: Daiwa Securities Group: possible leak of personal data of about 110,000 people, strengthens countermeasuresData breach · Finance · 1 report · 30 Oct 2026, 09:01 UTC
• JR West: JR West chairman apologises at Kansai Economic Federation press conference over customer data leakData breach · Transport · 1 report · 30 Oct 2026, 08:42 UTC
• Koade: Unauthorised access to Koade's Hanikuji Land may have leaked up to 7,622 people's personal data; malicious command execution and misuse of credentials confirmedData breach · Technology · 1 report · 30 Oct 2026, 06:19 UTC
• Unnamed target: Japanese IT firm says it is tracking hackers over leak of stolen dataData breach · Technology · 1 report · 30 Oct 2026, 06:03 UTC
• Bandai Namco Entertainment: Bandai Namco Entertainment: 346,240 users affected by data leakData breach · Media · 1 report · 30 Oct 2026, 05:30 UTC
• Sapporo City: Sapporo city official website fully restored; no data leak confirmed after PHP flaw impactService disruption · Government · 1 report · 30 Oct 2026, 03:36 UTC
• Unnamed target: Personal data leak from unauthorised access reaches 260 million records since April; Chief Cabinet Secretary Kihara says it is taken very seriouslyData breach · Other · 1 report · 30 Oct 2026, 03:05 UTC
• WASIMIL hotel management system: Unauthorised access attack on hotel management system WASIMIL; guest information used in fake payment emailsData breach · Other · 1 report · 30 Oct 2026, 03:00 UTC
• Iris Ohyama: Iris Ohyama online store hit by unauthorised access; information leak under investigationData breach · Retail · 1 report · 30 Oct 2026, 00:43 UTC
• Japan Airlines: Japan Airlines says Amadeus breach exposed data of about 92,000 customersData breach · Transport · 12 reports · 30 Oct 2026, 00:42 UTC
• Unnamed target: Japan asks mobile operators to block website linked to GMO data leakData breach · Other · 1 report · 29 Oct 2026, 23:22 UTC
• Entouch: Ransomware attack hits Entouch, which runs remote detailing and other servicesRansomware · Other · 2 reports · 29 Oct 2026, 23:05 UTC
• Good Smile Company: Hacker attack on Good Smile Company exposes card details of 2,800 customersData breach · Retail · 7 reports · 29 Oct 2026, 17:43 UTC
• Capcom: Capcom ID data breach hits 11.7 million accounts: what players should doData breach · Technology · 131 reports · 29 Oct 2026, 16:39 UTC
• Unnamed target: Two Japanese airlines report passengers data breachData breach · Transport · 1 report · 29 Oct 2026, 13:47 UTC
• GMO Internet: After a cyber attack, GMO was the victim of extortion demanding nearly 1,300 billion Vietnamese dongRansomware · Technology · 31 reports · 29 Oct 2026, 07:13 UTC
• Payどん: Possible personal data leak from unauthorised access to contractor of Kagoshima's Pay-don cashless campaign; email notifications halted and premium gift voucher sales postponedData breach · Government · 4 reports · 29 Oct 2026, 06:55 UTC
• NEL: Unauthorised access cyberattack on NEL may have leaked personal data of 235,329 osina membersData breach · Technology · 1 report · 29 Oct 2026, 06:40 UTC
• Jumonji Gakuen Women's University: Cyber attack possibly hit Jumonji Gakuen Women's University system last month, still unusable, possible personal data leakOther attack · Education · 3 reports · 29 Oct 2026, 04:07 UTC
• Japan Basketball Association: Japan Basketball Association website restored after about three weeks offline following ransomware attack, restored from backupsRansomware · Other · 1 report · 29 Oct 2026, 04:00 UTC
• Benefit One: Unauthorised access at Benefit One's contractor leaks personal data of about 29,000 people using Saison member perks serviceData breach · Other · 1 report · 29 Oct 2026, 03:40 UTC
• Kyushu University: Unauthorised access to Kyushu University alumni email delivery service leads to possible personal data leak, up to 9,999 registrations affectedData breach · Education · 3 reports · 29 Oct 2026, 03:23 UTC
• Unnamed target: AI divides up cyber attacks: 44 agents were found targeting Japanese organisationsOther attack · Other · 1 report · 29 Oct 2026, 03:15 UTC
• Skyticket: Successive personal data leaks: about 32,000 records including bank accounts at the operator of Sky Ticket, about 380,000 at Medicare Life, and unauthorised access confirmed on the METI websiteData breach · Transport · 8 reports · 29 Oct 2026, 03:10 UTC
• Okinawa Prefecture: Okinawa Prefecture outreach course applicants' information may have leaked; prefectural environment division had outsourced the workData breach · Government · 1 report · 29 Oct 2026, 01:00 UTC
• Maruki Medical Instruments: Cyber attack on Maruki Medical Instruments takes core systems down, orders taken by faxService disruption · Health · 1 report · 28 Oct 2026, 23:05 UTC
• IDCF Cloud: What happens when the core of a cloud service is seized? The full story of the IDCF ransomware attack that stopped virtual servers at 495 companiesRansomware · Technology · 4 reports · 28 Oct 2026, 22:45 UTC
• Sony: Data breach at Sony exposes 2.5 million customersData breach · Technology · 13 reports · 28 Oct 2026, 20:00 UTC
• Bandai Namco: Bandai Namco data breach: Over 300,000 users affected by third-party leakData breach · Technology · 4 reports · 28 Oct 2026, 18:05 UTC
• Japan Airlines, Sky Ticket, Flower Cupid: Japan Airlines, Sky Ticket, Flower Cupid and others report personal data leaks from unauthorised access one after anotherData breach · Transport · 1 report · 28 Oct 2026, 16:03 UTC
• Times Car: Times Car reports ¥5.5 billion loss as firms brace for data breach falloutData breach · Transport · 23 reports · 28 Oct 2026, 15:22 UTC
• Yokohama City: Yokohama city emergency alert system may have leaked personal data in Naka and Nishi wards after unauthorised access at a contractorData breach · Government · 3 reports · 28 Oct 2026, 15:00 UTC
• Park24: Times Car users in Japan prepare lawsuit against Park24 over major data breachData breach · Transport · 10 reports · 28 Oct 2026, 13:18 UTC
• NEC: NEC apologises for customer damage from cyber attack on contractorOther attack · Technology · 9 reports · 28 Oct 2026, 12:54 UTC
• Don Quijote: Don Quijote may have leaked customer information after a contractor was hit by unauthorised accessData breach · Retail · 2 reports · 28 Oct 2026, 11:55 UTC
• Flower Cupid: Flower delivery service Hanakyupitto's e-commerce member data leaked, up to 4.23 million recordsData breach · Retail · 4 reports · 28 Oct 2026, 11:40 UTC
• Hiroshima City: Possible leak of data on 437 children after a daily log was lost at a Hiroshima city-run facilityData breach · Government · 1 report · 28 Oct 2026, 10:05 UTC
• NTT Docomo: NTT Docomo: personal data of about 440,000 leaked from Docomo Hikari via unauthorised access at contractor So-netData breach · Technology · 4 reports · 28 Oct 2026, 07:00 UTC
• Kurokin Kasei: Kurokin Kasei may have leaked personal data of business partners, employees and job applicants in ransomware attack; announces MDR and multi-factor authentication measures to prevent recurrenceRansomware · Other · 1 report · 28 Oct 2026, 07:00 UTC
• Yumilink: Possible data leak at H2O Retailing subsidiary as member email addresses are exposed through unauthorised access to Yumilink's email delivery serviceData breach · Technology · 13 reports · 28 Oct 2026, 06:28 UTC
• Daihatsu: Daihatsu reports personal data leak from press site after unauthorised access to BlastMailData breach · Other · 2 reports · 28 Oct 2026, 06:26 UTC
• Rakuten Travel: Rakuten Travel hacked: 3.4 million records leaked, 36,000 credit card data exposedData breach · Technology · 3 reports · 28 Oct 2026, 03:25 UTC
• IDC Frontier: Japan's IDC Frontier discloses new ransomware findingsRansomware · Technology · 2 reports · 28 Oct 2026, 01:47 UTC
• Portas: Ransomware attack on Portas, contractor managing learning devices for Kushiro city elementary and junior high schoolsRansomware · Technology · 1 report · 27 Oct 2026, 23:05 UTC
• Satofull: Possible information leak at Satofull, the furusato nozei (hometown tax donation) portal, says Sano CityData breach · Other · 1 report · 27 Oct 2026, 18:54 UTC
• Resona Bank: Resona, Saitama Resona and Kansai Mirai banks may also have leaked customer informationData breach · Finance · 2 reports · 27 Oct 2026, 13:29 UTC
• Unnamed target: Hacker attack against Japanese company ends in $50 million ransom demandRansomware · Other · 1 report · 27 Oct 2026, 13:13 UTC
• SoftBank subsidiary: SoftBank subsidiary publishes cause and countermeasures after cyber attackOther attack · Technology · 1 report · 27 Oct 2026, 12:45 UTC
• Hyogo Prefecture: Possible data leak from Hyogo Prefecture startup support programme after unauthorised access to bulk email service BlastmailData breach · Government · 1 report · 27 Oct 2026, 11:58 UTC
• Sukesan Udon: Sukesan Udon may have leaked personal data of 20,000 employees, including reasons for leaving and wagesData breach · Retail · 1 report · 27 Oct 2026, 11:01 UTC
• Unnamed target: Sony subsidiary leaks 2.58 million records in unauthorised access, bank accounts also affectedData breach · Other · 1 report · 27 Oct 2026, 10:56 UTC
• Sony subsidiary: Sony subsidiary leaks 2.58 million records in unauthorised access, bank accounts also exposedData breach · Finance · 1 report · 27 Oct 2026, 10:55 UTC
• Tokyo Fire Department: Possible information leak from outsourced exam grading contractor, including past recruitment exam papers, Tokyo Fire DepartmentData breach · Government · 1 report · 27 Oct 2026, 10:09 UTC
• Smart EX / Express Reservation: Shinkansen booking services Smart EX and Express Reservation leak member data after unauthorised access to email delivery contractorData breach · Transport · 2 reports · 27 Oct 2026, 09:50 UTC
• Unnamed target: Trading platform rocked by Japan hack, $50m ransom noteRansomware · Finance · 1 report · 27 Oct 2026, 09:00 UTC
• Resona Group: Resona Group possible personal data leak from unauthorised access to Yumilink system, including email addresses and customer management numbersData breach · Finance · 4 reports · 27 Oct 2026, 07:28 UTC
• Nissho Denki Seisakusho: Ransomware attack on Hokkaido's Nissho Denki Seisakusho claimed by Qilin groupRansomware · Other · 1 report · 27 Oct 2026, 07:00 UTC
• Impress Research Institute: Notice of information leak at outsourcing vendor's email delivery system (first report)Data breach · Media · 1 report · 27 Oct 2026, 06:58 UTC
• Unnamed target: Japan vows to address cyber attack on FX with urgencyOther attack · Other · 1 report · 27 Oct 2026, 06:00 UTC
• Okinawa Tourist: Okinawa Tourist announces leak of personal data of up to about 730,000 peopleData breach · Transport · 6 reports · 27 Oct 2026, 05:07 UTC
• Unnamed target: Japan vows to address cyber attack on FX with urgencyOther attack · Finance · 1 report · 27 Oct 2026, 02:32 UTC
• Unnamed target: Japan vows to address cyber attack on FX with urgencyOther attack · Other · 1 report · 27 Oct 2026, 02:29 UTC
• JR East, JR Central, JR West: Shinkansen "Smart EX" data leak: unauthorised access at a contractor, announced by three JR companiesData breach · Transport · 1 report · 27 Oct 2026, 02:21 UTC
• Unnamed target: First cabinet-level ministers' meeting on a series of cyber attacks; emergency countermeasures to be compiled by next weekOther attack · Other · 1 report · 27 Oct 2026, 02:09 UTC
• Unnamed target: Japan holds first ministerial meeting over a string of cyber attacks, with emergency countermeasures to be compiled by next weekOther attack · Other · 1 report · 27 Oct 2026, 02:09 UTC
• Joshin Denki: Millions of records at risk: Joshin suffers hacker attack in JapanData breach · Retail · 7 reports · 27 Oct 2026, 01:44 UTC
• Unnamed target: Car-share service data leak victims to file compensation suitData breach · Transport · 1 report · 27 Oct 2026, 01:32 UTC
• Iwaki Film Commission Council: Personal data of 300 extras possibly leaked, Iwaki Film Commission CouncilData breach · Other · 1 report · 26 Oct 2026, 23:59 UTC
• Ibaraki Prefecture: Ibaraki Prefecture website restored after ransomware attack, no personal data leak confirmedRansomware · Government · 1 report · 26 Oct 2026, 22:50 UTC
• JR Central: Personal information leaked from Shinkansen booking system, announced by JR Central and othersData breach · Transport · 4 reports · 26 Oct 2026, 22:41 UTC
• Unnamed target: Japanese company to pay users compensation after cyber attackData breach · Other · 1 report · 26 Oct 2026, 19:52 UTC
• Furukawa Electric: Possible personal data leak at Furukawa Electric subsidiary; suspected unauthorised access to shipping management web systemData breach · Technology · 1 report · 26 Oct 2026, 15:45 UTC
• Ymirlink: Cyberattack on Ymirlink exposes data on JR train reservation service usersData breach · Transport · 1 report · 26 Oct 2026, 12:41 UTC
• Unnamed target: Japan: company to compensate users affected by cyberattackOther attack · Other · 1 report · 26 Oct 2026, 11:53 UTC
• Cuenote FC: Possible information leak at email delivery service Cuenote FC (with update added at 5pm on October 27)Data breach · Technology · 1 report · 26 Oct 2026, 11:46 UTC
• Nagoya Bank: Nagoya Bank may have leaked customer informationData breach · Finance · 1 report · 26 Oct 2026, 11:00 UTC
• TrustBank: FAQ on personal data leak caused by unauthorised access, for donorsData breach · Technology · 1 report · 26 Oct 2026, 07:51 UTC
• Unnamed target: Five Japanese FX brokers confirm hackers placed trades after server host breachOther attack · Finance · 1 report · 26 Oct 2026, 07:11 UTC
• Yomiuri Shimbun WEST: Yomiuri WEST's 'Yomipost' possibly leaked personal information through unauthorised access, KagawaData breach · Media · 1 report · 26 Oct 2026, 06:55 UTC
• Times: Times issue: class action planned over damage from information leakData breach · Other · 3 reports · 26 Oct 2026, 06:35 UTC
• Onamae Desktop Cloud: Japan's Onamae Desktop Cloud breach affects up to 27,000 serversData breach · Technology · 3 reports · 26 Oct 2026, 05:38 UTC
• Kagoshima City: Possible personal data leak of up to about 3,000 people's names and email addresses from applicants to Furespo swimming classes, Kagoshima CityData breach · Government · 1 report · 26 Oct 2026, 04:32 UTC
• Japan Government: Japan Government to Hold Ministerial Meeting on Cyberattack Response Tonight; PM Takaichi to Order Emergency MeasuresOther attack · Government · 1 report · 26 Oct 2026, 03:55 UTC
• Tokyo Metropolitan Government: Up to about 16,000 records leaked from Tokyo farm volunteer programme after intrusion into contractor's delivery serviceData breach · Government · 2 reports · 26 Oct 2026, 03:29 UTC
• Unnamed target: Japanese government to hold ministerial meeting on evening of the 26th over cyber attack response; PM to order emergency measuresOther attack · Government · 1 report · 26 Oct 2026, 03:14 UTC
• Eストアー: Estore publishes final report on personal data leak from unauthorised access on 1 August 2026Data breach · Technology · 2 reports · 26 Oct 2026, 03:00 UTC
• Unnamed target: Chief Cabinet Secretary calls information leak serious and says countermeasures are urgentData breach · Other · 1 report · 26 Oct 2026, 02:33 UTC
• The Pokémon Company: Three Pokémon titles including Pokémon HOME, halted amid PHP controversy, to resume on the 22nd; no announcement yet on whether data was leakedService disruption · Technology · 1 report · 26 Oct 2026, 02:00 UTC
• Tome City: Miyagi city of Tome may have leaked personal data of marriage support programme registrants after unauthorised access to contractorData breach · Government · 2 reports · 26 Oct 2026, 01:35 UTC
• Mos Card: Japan's Mos Card data breach: 1.13 million records leaked after unauthorized access to contractor's server; card numbers and PINs affectedData breach · Finance · 2 reports · 26 Oct 2026, 01:35 UTC
• Ministry of Land, Infrastructure, Transport and Tourism: Japan transport ministry's 2024 home energy-saving application system tampered with; personal data of 23,918 people may have leakedData breach · Government · 3 reports · 26 Oct 2026, 01:24 UTC
• Sagawa Express: Information leaks reported at Digital Agency too, as Sagawa Express data breach reaches up to 53.23 million recordsData breach · Transport · 18 reports · 26 Oct 2026, 01:00 UTC
• Nomura Securities: Nomura Securities: possible customer information leak via unauthorised access at an outsourced contractor; email addresses affected, trading account information not includedData breach · Finance · 4 reports · 26 Oct 2026, 00:49 UTC
• Medley: Medley confirms leak of patient personal data from its "@link" service, including login IDs, passwords, medical providers and payment historyData breach · Health · 1 report · 26 Oct 2026, 00:26 UTC
• SK Logi: Ransomware attack on SK Logi confirmed, with some internal information leakedRansomware · Transport · 1 report · 25 Oct 2026, 23:05 UTC
• Hida Takayama Travel Guide: Hida Takayama tourism website "Hida Takayama Travel Guide" hit by unauthorised access, some information leakedData breach · Government · 1 report · 25 Oct 2026, 22:39 UTC
• WMail (ワイメール): Summary of cyber attack via unauthorised access to email delivery service WMail (ワイメール)Data breach · Technology · 1 report · 25 Oct 2026, 21:48 UTC
• Hirokawa Town: Caution notice on measures after information leak from unauthorised access (for residents and businesses)Data breach · Government · 1 report · 25 Oct 2026, 20:31 UTC
• Ekipa: Possible leak of personal data of users of JR Shizuoka Station underground parking 'Ekipa'; man demands money by phoneData breach · Transport · 2 reports · 25 Oct 2026, 03:08 UTC
• Toda Corporation: Toda Corporation disclosed a data breach: what it means for Toda stockData breach · Other · 1 report · 25 Oct 2026, 00:28 UTC
• Pizza Hut Japan: Pizza Hut Japan suffers data breach exposing customer informationData breach · Retail · 1 report · 24 Oct 2026, 22:13 UTC
• Shizuoka City: Shizuoka: possible leak of information on people who lost parking tickets, at Shizuoka City contractorData breach · Government · 2 reports · 24 Oct 2026, 20:00 UTC
• Furusato Choice: Personal information leak from Furusato Choice; Iwaki City urges citizens and taxpayers to be cautiousData breach · Technology · 19 reports · 24 Oct 2026, 14:08 UTC
• Blastmail: Unauthorised access to Blastmail may have leaked personal data of about 4,300 people across three Nagano businessesData breach · Technology · 1 report · 24 Oct 2026, 04:20 UTC
• Iwai Cosmo Securities: Cyber attack on Iwai Cosmo Securities aimed at market manipulation, possibly to inflate prices through unauthorised trades, chairman saysFraud / phishing · Finance · 14 reports · 24 Oct 2026, 02:25 UTC
• Lindt: Chocolate brand Lindt: personal data of 3,147,469 online shop members leaked in cyber attack on Future ShopData breach · Retail · 1 report · 23 Oct 2026, 22:34 UTC
• Ministry of the Environment: Environment Ministry says up to 22,000 newsletter sign-up records may have leaked in unauthorised accessData breach · Government · 1 report · 23 Oct 2026, 20:00 UTC
• OTS: OTS data leak affects up to 730,000 people; company confirms information matches its holdings and apologises deeplyData breach · Other · 2 reports · 23 Oct 2026, 20:00 UTC
• Arcadia: Arcadia apologises at press conference over information leak from unauthorised accessData breach · Other · 4 reports · 23 Oct 2026, 16:20 UTC
• Unnamed target: Japan car-sharing operator to offer users $19 each after data breachData breach · Transport · 1 report · 23 Oct 2026, 15:24 UTC
• Unnamed target: Japan considers data leak and cyberattack a "serious crisis"Data breach · Other · 1 report · 23 Oct 2026, 11:48 UTC
• Tokamachi and Nagaoka city governments: Possible information leak after unauthorised access to email distribution system of Tokamachi and Nagaoka cities, NiigataData breach · Government · 1 report · 23 Oct 2026, 11:43 UTC
• Tokyo Metro: Tokyo Metro: email addresses of about 80,000 leaked, second leak in a monthData breach · Transport · 1 report · 23 Oct 2026, 11:28 UTC
• Nagano Prefecture: Nagano Prefecture may have leaked personal data of about 4,300 newsletter subscribers after contractor suffered unauthorised accessData breach · Government · 1 report · 23 Oct 2026, 11:24 UTC
• Mitsukan: Mitsukan may have leaked personal information including namesData breach · Other · 2 reports · 23 Oct 2026, 11:01 UTC
• Unnamed target: Personal data leaks continue one after another, PHP vulnerability issue also on the 23rd, KagoshimaData breach · Other · 1 report · 23 Oct 2026, 10:45 UTC
• Andesti, Xebio, Treasure Factory: Information leak at Andesti, Xebio and Treasure FactoryData breach · Retail · 1 report · 23 Oct 2026, 10:17 UTC
• AND ST HD: Andesty HD possibly leaks 2.5 million records including names and addresses (Kyodo)Data breach · Other · 2 reports · 23 Oct 2026, 10:17 UTC
• Kyoto Chubu Wide-area Fire Department: Kyoto Chubu Wide-area Fire Department may have leaked personal data of emergency reporting system registrantsData breach · Government · 1 report · 23 Oct 2026, 10:13 UTC
• G-YET (Mac House): G-YET (Mac House) newsletter sign-ups may have leaked personal information after unauthorised access to BlastmailData breach · Retail · 1 report · 23 Oct 2026, 10:07 UTC
• Unnamed target: Information-leak app company holds press conference: "Brute-force attack, not something a human would do"Data breach · Technology · 1 report · 23 Oct 2026, 10:03 UTC
• Kanazawa City Fire Department: Unauthorised access to Kanazawa city fire department email service may have leaked information on 1,700 businessesData breach · Government · 1 report · 23 Oct 2026, 09:12 UTC
• Studio Co., Ltd.: Possible personal information leak from unauthorised access at Studio Co., Ltd.Data breach · Other · 4 reports · 23 Oct 2026, 09:00 UTC
• Nikkei: Nikkei hit by second cyber attack in a month, sensitive data exposedData breach · Media · 7 reports · 23 Oct 2026, 08:39 UTC
• Shima Blue Creator: Possible information leak due to unauthorised access to Shima Blue CreatorData breach · Government · 1 report · 23 Oct 2026, 08:29 UTC
• Renta!: Renta! discloses unauthorised access; member data may have leaked, service suspension continuesData breach · Media · 1 report · 23 Oct 2026, 08:02 UTC
• HIS subsidiary: HIS subsidiary may have leaked personal data of about 140,000 people via unauthorised access at outsourced provider Raksul Light CloudData breach · Other · 1 report · 23 Oct 2026, 07:10 UTC
• Digital Agency: Digital Agency reports data breach via website vendorData breach · Government · 2 reports · 23 Oct 2026, 03:01 UTC
• Tohoku Electric Power subsidiary: Tohoku Electric subsidiary may have leaked up to 100,000 members' data in unauthorised accessData breach · Energy / utilities · 1 report · 23 Oct 2026, 00:26 UTC
• Unnamed target: Prefecture's migration newsletter may have leaked personal information after unauthorised accessData breach · Government · 1 report · 22 Oct 2026, 23:24 UTC
• Nagoya IT company: Unauthorised access to a service provided by a Nagoya IT company for some municipalities, with possible leak of personal informationData breach · Technology · 1 report · 22 Oct 2026, 20:10 UTC
• New Japan Pro-Wrestling: New Japan Pro-Wrestling newsletter service hit by unauthorised access, possible personal data leakData breach · Media · 1 report · 22 Oct 2026, 19:40 UTC
• Japanese police: Japan's police investigating large data leak after cyberattack on emergency systemData breach · Government · 6 reports · 22 Oct 2026, 18:00 UTC
• Unnamed target: Osaka brokerage breach raises third-party cyber risk questions for insurersData breach · Finance · 1 report · 22 Oct 2026, 14:44 UTC
• Meitetsu Travel Service: Meitetsu Travel Service: possible leak of personal data of about 130,000 members after unauthorised accessData breach · Retail · 3 reports · 22 Oct 2026, 11:58 UTC
• Niigata Nippo: Niigata Nippo publisher says data of over 250,000 people may have leaked after unauthorised accessData breach · Media · 2 reports · 22 Oct 2026, 11:48 UTC
• JR Shikoku: JR Shikoku may have leaked up to about 30,000 records in unauthorised access, TokushimaData breach · Transport · 1 report · 22 Oct 2026, 11:25 UTC
• Tokamachi City: Impact of cyber attack and unauthorised access - Tokamachi CityOther attack · Government · 1 report · 22 Oct 2026, 10:33 UTC
• NTT Solmare: NTT Solmare's Comic Seymour announces up to about 4.2 million records leaked in unauthorised accessData breach · Media · 1 report · 22 Oct 2026, 09:30 UTC
• Ogata village: Ogata village may have leaked personal data of hometown tax donors through unauthorised access at Sagawa ExpressData breach · Government · 1 report · 22 Oct 2026, 09:20 UTC
• Tamura City: Possible personal data leak after unauthorised access in Tamura, FukushimaData breach · Government · 1 report · 22 Oct 2026, 09:17 UTC
• Ministry of Health, Labour and Welfare: Unauthorised access at outsourcing contractor of Japan's health ministry may have leaked personal data of up to 595 people; no secondary harm confirmedData breach · Government · 1 report · 22 Oct 2026, 08:47 UTC
• Toyama Prefecture: Possible leak of personal information from over 8,000 items after unauthorised access to a corporate information site run by Toyama PrefectureData breach · Government · 1 report · 22 Oct 2026, 08:42 UTC
• Osaka University: Osaka University may have leaked personal data of about 78,000 people via contractor NEC's unauthorised operationData breach · Education · 11 reports · 22 Oct 2026, 07:39 UTC
• Unnamed target: Cyber attack hits company that NEC outsources system development and maintenance work toOther attack · Technology · 1 report · 22 Oct 2026, 07:00 UTC
• Comic Seymour: Comic Seemore: personal data of up to about 4.2 million people leakedData breach · Media · 6 reports · 22 Oct 2026, 07:00 UTC
• Unnamed target: ICT company says information leak was caused by attack exploiting PHP vulnerability, later correctedData breach · Technology · 1 report · 22 Oct 2026, 07:00 UTC
• Housing Energy Saving 2024 Campaign: Possible leak of registered business operator information from the 2024 housing energy-saving campaignData breach · Government · 1 report · 22 Oct 2026, 07:00 UTC
• Baltec: Baltec suffers service outage from cyber attack, possible data leak (article corrected)Service disruption · Other · 1 report · 22 Oct 2026, 06:28 UTC
• Nagasaki Prefectural Police: Nagasaki police may have leaked personal data of about 3,500 people; found in a probe after unauthorised access at other prefectural police, all using the 'Arcadia' systemData breach · Government · 1 report · 22 Oct 2026, 06:17 UTC
• SmartHR: SmartHR warns of possible information leak after unauthorised access to its no-code web platform StudioData breach · Technology · 1 report · 22 Oct 2026, 05:09 UTC
• JFE Chemical: JFE Chemical confirms unauthorised access and information leak, possibly including business partner and employee dataData breach · Other · 1 report · 22 Oct 2026, 04:08 UTC
• Burger King Japan: Data breach hits 11 million Burger King Japan customersData breach · Retail · 13 reports · 22 Oct 2026, 03:45 UTC
• Unnamed target: Personal information leaked from furusato nozei donation intermediary site; Saga Prefecture issues warningData breach · Other · 1 report · 22 Oct 2026, 03:44 UTC
• Isumi City: Possible leak of personal information - Isumi CityData breach · Government · 1 report · 22 Oct 2026, 03:19 UTC
• Unnamed target: Police urgently convene anti-cyberterrorism council to discuss infrastructure operators after information leak from unauthorised accessData breach · Other · 1 report · 22 Oct 2026, 03:03 UTC
• Japan Times: Unauthorised access at a Japan Times group company; The Japan Times Online not affectedOther attack · Media · 2 reports · 21 Oct 2026, 23:05 UTC
• Japanese National Police Agency: Cyber attack in Japan may have breached personal data of 125,000 police officersData breach · Government · 1 report · 21 Oct 2026, 16:00 UTC
• Namegawa Town: Notice about information leak due to unauthorised access, Namegawa TownData breach · Government · 1 report · 21 Oct 2026, 15:23 UTC
• Aeon Group: Aeon Group's 13 companies hit by unauthorised access at 42 sites; data leak under investigationOther attack · Retail · 5 reports · 21 Oct 2026, 12:56 UTC
• Prefectural police forces: Personal data of 125,000 police officers from 20 prefectural police forces possibly leaked, including names and addressesData breach · Government · 1 report · 21 Oct 2026, 12:50 UTC
• Kurume City: Personal information leaked from furusato nozei (hometown tax donation) site used by Kurume CityData breach · Government · 1 report · 21 Oct 2026, 11:31 UTC
• Aomori City: Unauthorised access incidents continue daily; Aomori City and Aomori Prefectural Police email newsletters suspendedService disruption · Government · 1 report · 21 Oct 2026, 11:11 UTC
• Nagaoka City: Nagaoka city announces possible personal information leak from shared homepage of Wajima Auto Campground and Umami Forest ParkData breach · Government · 1 report · 21 Oct 2026, 11:10 UTC
• Osaka Metropolitan University: Large-scale system failure at Osaka Metropolitan University caused by cyber attack on NEC's subcontractorService disruption · Education · 5 reports · 21 Oct 2026, 09:28 UTC
• NEC subcontractor: Cyberattack on NEC subcontractor causes system failures and data leak at multiple customersData breach · Technology · 4 reports · 21 Oct 2026, 07:00 UTC
• Osumi Kimotsuki Regional Fire Association: Possible information leak after unauthorised access to the contractor of the NET119 emergency reporting systemData breach · Government · 1 report · 21 Oct 2026, 07:00 UTC
• Unnamed target: Chinese-linked AI agent 'ARTEX' behind cyber attacks; information leak damage continues, including police and national projectsData breach · Government · 1 report · 21 Oct 2026, 07:00 UTC
• Car Sensor: Up to 3.71 million personal records may have leaked from Car Sensor amid a series of unauthorised access incidents, with financial institutions also targetedData breach · Other · 4 reports · 21 Oct 2026, 07:00 UTC
• Recruit: Used-car site Carsensor may have leaked personal data, up to 3.7 million records, Recruit announcesData breach · Other · 1 report · 21 Oct 2026, 07:00 UTC
• Unnamed target: Emperor and Empress to visit Osaka for fisheries festival; schedule changed due to cyber attackOther attack · Government · 1 report · 21 Oct 2026, 07:00 UTC
• Unnamed target: Emperor and Empress's Osaka visit changed due to cyber attack; November sea-nurturing festivalService disruption · Government · 1 report · 21 Oct 2026, 07:00 UTC
• Gunma Prefectural Police: Data of all 3,700 Gunma Prefectural Police staff may have leaked in Arcadia unauthorised access case, with concern it could be used in fake-police scamsData breach · Government · 1 report · 21 Oct 2026, 07:00 UTC
• Square Enix: Final Fantasy XIV suffers data leak and Square Enix recommends password changesData breach · Technology · 3 reports · 21 Oct 2026, 07:00 UTC
• Unnamed target: Personal information leaks from unauthorised access continue, with more consultations to Tokyo Metropolitan PoliceData breach · Other · 1 report · 21 Oct 2026, 03:00 UTC
• Chiba Prefecture: Chiba Prefecture: personal data may have leaked from four projects including a youth meeting support programmeData breach · Government · 1 report · 20 Oct 2026, 12:56 UTC
• Sourcenext: Sourcenext says API abuse exposed data from up to 22.5 million customer recordsData breach · Technology · 3 reports · 20 Oct 2026, 12:25 UTC
• Unnamed target: Information leaked after cyber attacks; possible misuse of a Chinese-language AI agent, traces found in attacks on 80 Japanese companiesData breach · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Helpfeel: Investigation results and apology for information leak from unauthorised access to Gyazo (third report)Data breach · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• KTS Kagoshima Television: Possible leak of personal information due to unauthorised accessData breach · Media · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Cyber attacks on Japanese companies may partly use Chinese-made AI; about 80 firms targetedOther attack · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Globee: Globee discloses unauthorised third-party access and possible personal data leakData breach · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• Nifty: Nifty also leaks information, up to 540,000 optical fibre application recordsData breach · Technology · 7 reports · 20 Oct 2026, 07:00 UTC
• Kanagawa Prefectural Police: Staff data may also have leaked from Kanagawa and Tochigi police and others after unauthorised access at a system operatorData breach · Government · 2 reports · 20 Oct 2026, 07:00 UTC
• Japanese companies: Cyber attacks on Japanese companies likely used Chinese AI, private survey confirmsOther attack · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Hankyu Hanshin Department Stores: Hankyu Hanshin Department Stores personal data leak affects 1.26 million records including customer names and email addressesData breach · Retail · 5 reports · 20 Oct 2026, 07:00 UTC
• Times Car; JR East: Series of data leaks at Times Car, JR East and others, with about 60 million records exposed in two weeks, possibly linked to AI misuseData breach · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Ashikaga City: Ashikaga mayor apologises at press conference over unauthorised access to crematorium system, possible personal data leakData breach · Government · 1 report · 20 Oct 2026, 07:00 UTC
• LIXIL: LIXIL's L-Pocket app hit by unauthorised access, personal data of 3,379 people leaked; business support app temporarily suspendedData breach · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Cyber attack on NEC subcontractor stops customer systems and leaks personal data; stolen legitimate account usedData breach · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• Entach: Ransomware attack on Toho Holdings subsidiary Entach; leak of healthcare worker and interview booking information confirmedRansomware · Health · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Information leaks also reported in Aomori Prefecture; unauthorised access to a ticket sales serviceData breach · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Chief Cabinet Secretary says it is not yet certain whether AI was used in domestic cyber attackOther attack · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Possible leak of over 23,000 records from national energy-saving housing programmeData breach · Government · 1 report · 20 Oct 2026, 07:00 UTC
• Linkstation: Member information leaked from Linkstation (Aomori)Data breach · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Fukuoka Prefectural Police: Information of about 11,000 people possibly leaked in unauthorised access to Arcadia system, Fukuoka Prefectural PoliceData breach · Government · 3 reports · 20 Oct 2026, 07:00 UTC
• Niigata Prefecture: Niigata Prefecture portal may have leaked personal data through unauthorised access to Tokyo-based Studio service; Minami Ward site in Niigata City also possibly affectedData breach · Government · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Suspected cyber attack linked to Chinese AI; chief cabinet secretary says investigation will include possible foreign involvementOther attack · Government · 1 report · 20 Oct 2026, 07:00 UTC
• Hachinohe City: Personal data of 49 alumni event participants may have leaked, Hachinohe city announcesData breach · Government · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Attacks aimed at Japan may come from source using China-developed AI to target specific countries and sectors, with service suspensions following unauthorised accessOther attack · Other · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Personal data of about 2,200 prefectural police officers and staff may have leaked after an Osaka IT company was illegally accessedData breach · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• Unnamed target: Information leak at ticket purchase service; Kumamoto Nichinichi also used it in part; possible leak of 1,125 people's informationData breach · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• Toho Gas: Possible information leak at Toho Gas, with up to 100 records possibly exposed; no misuse confirmed so farData breach · Energy / utilities · 1 report · 20 Oct 2026, 07:00 UTC
• Ambition DX Holdings: Ambition DX Holdings confirms about 140,000 files taken in cyber attack; up to 580,000 personal records may have leaked; ransomware group has claimed responsibilityRansomware · Technology · 1 report · 20 Oct 2026, 07:00 UTC
• Nissui subsidiary: Nissui subsidiary resumes normal operations after two weeks; about 1,200 companies were affected at one pointService disruption · Other · 1 report · 20 Oct 2026, 02:13 UTC
• JETRO: JETRO reports 743 personal data leaksData breach · Government · 4 reports · 19 Oct 2026, 14:03 UTC
• Keio Railway subsidiaries: Qilin claims responsibility for ransomware attack on Keio Railway subsidiariesRansomware · Transport · 1 report · 19 Oct 2026, 11:06 UTC
• Daiichi Kosho: Data breach at Japanese karaoke system maker Daiichi Kosho affects more than 8.7 million peopleData breach · Technology · 2 reports · 19 Oct 2026, 07:00 UTC
• FANCL: FANCL and Attenir suffer data breach affecting 780,000 customers, exposing addresses, names and phone numbersData breach · Retail · 2 reports · 19 Oct 2026, 07:00 UTC
• Yamato, Estore, Nikkei: Yamato, Estore and Nikkei report major data leaks in JapanData breach · Other · 1 report · 19 Oct 2026, 07:00 UTC
• Toho Holdings: Toho Holdings leaks personal information of medical workersData breach · Health · 2 reports · 19 Oct 2026, 07:00 UTC
• Unnamed target: Cyberattack damage: used car sites and other services suspended one after anotherService disruption · Retail · 1 report · 19 Oct 2026, 07:00 UTC
• X Mile: X Mile: possible leak of personal information from inquiry form after unauthorised access by a third partyData breach · Transport · 1 report · 19 Oct 2026, 07:00 UTC
• Unnamed target: Cyber attack halts crematorium booking system; deceased people's information may have leaked (Tochigi)Data breach · Government · 1 report · 19 Oct 2026, 07:00 UTC
• Nippon Television: Nippon TV president vows to further strengthen cyber defences after group information leakData breach · Media · 1 report · 19 Oct 2026, 07:00 UTC
• DIGYM: DIGYM hit by unauthorised-access cyberattack; access to all sites temporarily blocked while possible personal data leak is investigatedData breach · Other · 1 report · 19 Oct 2026, 07:00 UTC
• Hakata Hankyu; Fukuoka Convention Center: Possible personal information leak at Hakata Hankyu and Fukuoka Convention CenterData breach · Retail · 1 report · 19 Oct 2026, 07:00 UTC
• Saitama Prefectural Police: Saitama Prefectural Police may have leaked personal data of 13,000 people through unauthorised access at a contractorData breach · Government · 4 reports · 19 Oct 2026, 07:00 UTC
• Yamato Transport: Yamato Transport data leak reaches 5.31 million records; Nikkei reports 1.83 million, with unauthorised access continuingData breach · Transport · 4 reports · 19 Oct 2026, 07:00 UTC
• Japan Post: Japan Post point site possibly leaked data on 249 cases (Kyodo)Data breach · Other · 2 reports · 19 Oct 2026, 07:00 UTC
• Hiroshima Prefectural Police: Repeated personal data leaks at Hiroshima police raise crisis-management questions in prefectural assemblyData breach · Government · 1 report · 19 Oct 2026, 07:00 UTC
• Fukuyama City: Possible unauthorised access to hometown tax donation portal; Fukuyama City suspends service and investigates possible personal data leakData breach · Government · 1 report · 19 Oct 2026, 07:00 UTC
• Kagawa Prefectural Police: Unauthorised access, possible information leak also at Kagawa Prefectural PoliceData breach · Government · 1 report · 18 Oct 2026, 07:00 UTC
• Tokushima Prefectural Police: Tokushima Prefectural Police may have leaked data on about 1,900 officers and staff after unauthorised access to Arcadia; spoofing and targeted attacks fearedData breach · Government · 1 report · 18 Oct 2026, 07:00 UTC
• Tohoku Electric Power Frontier: Tohoku Electric Power group company Tohoku Electric Power Frontier possibly leaks information after unauthorised accessData breach · Energy / utilities · 1 report · 18 Oct 2026, 07:00 UTC
• Geo Online: Unauthorised access confirmed at Geo Online amid a series of cyberattacks, with new orders suspendedData breach · Retail · 1 report · 18 Oct 2026, 07:00 UTC
• Wasabi Switch: Wasabi Switch hit again by unauthorised access cyber attack; stolen admin passwords used to steal order and email data, suspicious emails sent from store's genuine addressesData breach · Retail · 1 report · 18 Oct 2026, 07:00 UTC
• Hassha Oorai Net: Summary of unauthorised-access cyber attack on bus service provider Hassha Oorai Net, with multiple Japanese bus operators announcing incidents, including Irukа Kotsu (258 cases) and Chugoku Bus (17 cases)Data breach · Transport · 1 report · 18 Oct 2026, 07:00 UTC
• Shizuoka Prefecture: Shizuoka Prefecture to urgently inspect its managed websites after a series of personal data leaksData breach · Government · 1 report · 17 Oct 2026, 07:00 UTC
• Goshogawara District Fire Service Association: Possible leak of personal data expands to 8 administrative bodies in Aomori Prefecture, over 12,000 people affectedData breach · Government · 1 report · 17 Oct 2026, 07:00 UTC
• Wakayama Prefectural schools: Personal information may have leaked from 21 prefectural schools too, in IT company unauthorised access case, WakayamaData breach · Education · 1 report · 17 Oct 2026, 07:00 UTC
• KURUME MUSIC FES: Kurume City, Fukuoka Prefecture: personal information entered into the inquiry form of the KURUME MUSIC FES music event website may have been leakedData breach · Other · 1 report · 17 Oct 2026, 07:00 UTC