Investigating
Haebaru Town: Arcadia intrusion may have exposed disaster-mail and call-service registrant data
Disclosed Oct 20, 2026. SpeeCAN RAIDEN (Arcadia) intrusion may have exposed name/email/phone. No headcount.
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.
Investigating
Miyakojima City: Arcadia intrusion may have exposed disaster-mail registrant data
Disclosed Oct 20, 2026. Arcadia-operated disaster mail may have exposed emails and related registrant data. No headcount.
Confirmed
JETRO website breach exposes company contacts and staff information
Unauthorised access from October 14 exposed 743 personal-data items including company names and contact emails. A November 6 update added 142 event-registration contacts, 9,252 current/former staff and 19 vendor contacts.
Investigating
Kanuma City: Arcadia intrusion may have exposed data on 106 people related to 119 Raiden / Net119
Disclosed Oct 19, 2026. Notice states 106 people may have had data exposed. Using that published possible-leak headcount.
Investigating
Hashimoto City: SpeeCAN RAIDEN intrusion may have exposed Hashimoto disaster-mail registrant data
Disclosed/updated Oct 19, 2026. SpeeCAN RAIDEN Hashimoto disaster mail may have exposed personal data. No headcount.
Confirmed
Trustbank Furusato Choice: 4,454,097 member records leaked
Trustbank suspended services and posted a notice on October 19 after spotting unusual access, and on October 20 announced member data had leaked in an October 17 intrusion.
Confirmed
Ymir Link: personal data of client companies exfiltrated from Cuenote FC email platform
On October 16, 2026, Ymir Link found unauthorised access to some Cuenote FC email-delivery servers and announced on October 19 that personal data had been exfiltrated.
Investigating
Tosa City: vendor intrusion may have exposed 119RAIDEN and NET119 registrant data
Disclosed Oct 17, 2026. Up to 380 119RAIDEN and up to 300 NET119 records may have leaked. Maximum → blank.
Investigating
Shibayama Town: SpeeCAN RAIDEN intrusion may have exposed resident and staff mail registrant data
Disclosed Oct 16, 2026. Possible exposure of 1,277 resident-mail and 151 staff-mail registrants. Subsets not summed.
Investigating
Inami Town (Hyogo): Arcadia intrusion may have exposed staff and fire-corps mail registrant data
Disclosed Oct 16, 2026. Arcadia intrusion may have exposed staff name/email and some fire-corps name/email. Inami Anshin Net out of scope. No headcount.
Investigating
Possible exposure of 6,412 Raksul form-submission records through Studio
Raksul said 6,412 submission records from its service-information websites may have been exposed through the Studio vendor incident.
Confirmed
Nikkei reports about 1.83 million development-cloud entries leaked
Nikkei disclosed that unauthorized access on October 7 leaked approximately 1.83 million entries from a development-cloud environment.
Confirmed
Iwai Cosmo Securities: data of 4,611 online-trading customers leaked via contractor TradeWorks
Systems of TradeWorks, which operates Iwai Cosmo's online-trading platform, were accessed without authorisation and some customer data leaked; detected October 14.
Investigating
Wako City: SpeeCAN RAIDEN intrusion may have exposed notification registrant data
Disclosed Oct 16, 2026. SpeeCAN RAIDEN intrusion may have exposed personal data. No headcount.
Investigating
Aomori City: Arcadia SpeeCAN RAIDEN intrusion may have exposed disaster-mail and related registrant data
Disclosed Oct 16, 2026. About 4,900 disaster-mail, about 100 phone/FAX and about 2,900 staff safety-check registrants may have leaked. About/subsets → blank.
Investigating
Mima City: vendor intrusion may have exposed data on 328 disaster-notification registrants
Disclosed Oct 16, 2026 (delivery resumed same day). Possible exposure of name/phone/FAX/email for 328 call/FAX/mail registrants.
Investigating
Takarazuka City: vendor intrusion may have exposed 39 NET119 and 308 119RAIDEN registrants
Disclosed Oct 16, 2026. Possible exposure of 39 NET119 citizens and 308 119RAIDEN fire staff/corps. Subsets not summed.
Confirmed
FANCL and Attenir: e-commerce member data leaked (368,184 and 417,312 people respectively)
An October 15 internal review found the FANCL and Attenir e-commerce sites were accessed without authorisation October 3-10 and some member data leaked.
Investigating
Kameyama City: vendor intrusion may have exposed staff-assembly mail registrant data
Disclosed Oct 15, 2026. Staff-only assembly-mail intrusion may have exposed personal data. Citizen data and disaster app out of scope. No headcount.
Investigating
Takayama City: Arcadia intrusion may have exposed NET119 registrant data
Disclosed Oct 15, 2026. Arcadia NET119 intrusion may have exposed registrant personal data. No headcount.