Find incidents
Cyberattacks and data leaks that hit organizations in Japan. Filter by disclosure date, method, impact and status, or by where the affected organizations are, their industry or type and size.
327 results
Disclosed 2026-10-15Updated 2026-10-16Tokyo[Contained][Severity: Critical]
Sourcenext: member data leak[API abuse][Data leak]Leaked 22.5MOrganizations 1Disclosed 2026-10-15Updated 2026-10-15Tokyo[Contained][Severity: Critical]
Burger King: app member data leak[Intrusion][Data leak]Leaked 11.2MOrganizations 1Disclosed 2026-10-15Updated 2026-10-15Osaka, Tokyo[Investigating][Severity: Critical]
Daiwa Institute of Research: Naito Securities' online trading system intrusion[Intrusion][Data leak]Leaked 631Organizations 2Disclosed 2026-10-14Updated 2026-10-22Tokyo[Investigating][Severity: Critical]
Carry: Lili matching site server intrusion[Web app exploit][Data leak]Leaked 98.3KOrganizations 1Disclosed 2026-10-14Updated 2026-10-20Tokyo[Resolved][Severity: Critical]
Aena: unauthorized access to its shopping app[Intrusion][Data leak]Leaked 817.2KOrganizations 1Disclosed 2026-10-14Updated 2026-10-14Tokyo[Contained][Severity: Critical]
NTV Wands: FaveConnect unauthorized logins[Credential abuse][Data leak]Leaked 117.4KOrganizations 1Disclosed 2026-10-13Updated 2026-11-02Tokyo[Contained][Severity: Critical]
Myvo Fellows: member system intrusion leaks 426 people’s data; Myvo App discontinued[Intrusion][Data leak][Service outage]Leaked 426Organizations 1Disclosed 2026-10-13Updated 2026-10-30Tokyo[Investigating][Severity: Major]
East Japan Mitsubishi Motor Sales: Microsoft 365 unauthorized logins[Credential abuse][Data leak]Leaked 24.5KOrganizations 1Disclosed 2026-10-13Updated 2026-10-21Tokyo[Contained][Severity: Critical]
Fivot: IDARE intrusion[Web app exploit][Data leak]Leaked 129.7KOrganizations 1Disclosed 2026-10-13Updated 2026-10-16Tokyo[Investigating][Severity: Major]
Golf Digest Online: unauthorized access to its servers[Intrusion][Data leak][Service outage]Leaked 1.8KOrganizations 1Disclosed 2026-10-13Updated 2026-10-13Tokyo[Investigating][Severity: Critical]
Ride On Express: ransomware at Gin no Sara server supplier[Ransomware][Service outage][Data leak]Leaked 6.5MOrganizations 1Disclosed 2026-10-09Updated 2026-10-28Tokyo[Investigating][Severity: Critical]
Adventure: unauthorized access to skyticket servers[Intrusion][Data leak]Leaked 14.6MOrganizations 1Disclosed 2026-10-09Updated 2026-10-09Tokyo[Contained][Severity: Major]
coconala: Coconala Skill Market intrusion[Web app exploit][Data leak]Leaked 1.8KOrganizations 1Disclosed 2026-10-09Updated 2026-10-09Tokyo[Investigating][Severity: Critical]
Adventure: skyticket back-office system intrusion[Intrusion][Data leak]Leaked 17.8KOrganizations 1Disclosed 2026-10-09Updated 2026-10-09Tokyo[Resolved][Severity: Major]
Adventure: skyticket bus bookings exposed[Misconfiguration][Data leak]Leaked 12KOrganizations 1Disclosed 2026-10-08Updated 2026-10-21Aichi, Aomori, Hiroshima, Kanagawa, Osaka, Shizuoka, Tokyo[Investigating][Severity: Critical]
Commune: Commune intrusion[Intrusion][Data leak]Leaked 166.5KOrganizations 28Disclosed 2026-10-08Updated 2026-10-20Tokyo[Contained][Severity: Moderate]
Gakken: external server intrusion[Intrusion][Service outage]Organizations 3Disclosed 2026-10-08Updated 2026-10-19Tokyo[Resolved][Severity: Critical]
Lawson: Lawson ID intrusion[Intrusion][Data leak]Leaked 2.2MOrganizations 1Disclosed 2026-10-08Updated 2026-10-09Tokyo[Investigating][Severity: Critical]
Nippon Columbia Group: Daiichikosho contractor PC malware[Malware][Data leak]Leaked 8.7MOrganizations 2Disclosed 2026-10-08Updated 2026-10-09Tokyo[Contained][Severity: Critical]
Uzabase: NewsPicks admin tool intrusion[Web app exploit][Data leak]Leaked 362KOrganizations 1Disclosed 2026-10-08Updated 2026-10-08Tokyo[Contained][Severity: Major]
hi-ho: My Page impersonation logins[Phishing][Credential abuse][Data leak]Leaked 38.5KOrganizations 1Disclosed 2026-10-08Updated 2026-10-08Tokyo[Contained][Severity: Critical]
hi-ho: competing agency accesses customer pages[Phishing][Credential abuse][Data leak][Financial loss]Leaked 3.7KOrganizations 1Disclosed 2026-10-07Updated 2026-10-27Aichi, Fukuoka, Hiroshima, Ibaraki, Osaka, Tokyo[Ongoing][Severity: Critical]
IDC Frontier: ransomware attack on IDCF Cloud[Ransomware][Intrusion][Web app exploit][Service outage][Data leak]Leaked 4MOrganizations 495Disclosed 2026-10-07Updated 2026-10-07Tokyo[Investigating][Severity: Major]
Toda: unauthorized access to the payment system[Intrusion][Data leak]Leaked 7.2KOrganizations 1Disclosed 2026-10-06Updated 2026-10-10Tokyo[Contained][Severity: Critical]
dip: Baitoru NEXT intrusion[Web app exploit][Data leak]Leaked 3.9MOrganizations 1Disclosed 2026-10-06Updated 2026-10-06Tokyo[Investigating][Severity: Critical]
Iyaku Joho Net: Pharma DIGITAL intrusion[Intrusion][Data leak][Service outage]Leaked 514KOrganizations 2Disclosed 2026-10-06Updated 2026-10-06Tokyo[Contained][Severity: Critical]
Rakuten Mobile: Rakuten Drive admin credentials compromised[Credential abuse][Data leak]Leaked 15.4KOrganizations 1Disclosed 2026-10-06Updated 2026-10-06Tokyo[Investigating][Severity: Major]
Weathercaster Network: website defacement[Intrusion][Data leak][Site defacement][Service outage]Leaked 16KOrganizations 1Disclosed 2026-10-05Updated 2026-10-21Osaka, Tokyo[Ongoing][Severity: Critical]
Osaka Metropolitan University: NEC contractor attack disrupts systems[Ransomware][Credential abuse][Service outage][Data leak]Leaked 130KOrganizations 3Disclosed 2026-10-05Updated 2026-10-16Tokyo[Investigating][Severity: Critical]
Scala Communications: i-ask intrusion[Credential abuse][Data leak]Leaked 713.1KOrganizations 6Disclosed 2026-10-05Updated 2026-10-14Tokyo[Investigating][Severity: Critical]
GMO Research & AI: infoQ intrusion[Web app exploit][Data leak][Fraud][Service outage]Leaked 948.5KOrganizations 1Disclosed 2026-10-04Updated 2026-10-04Tokyo[Contained][Severity: Major]
Nikkei: Google Workspace unauthorized logins[Credential abuse][Data leak]Leaked 1.6KOrganizations 1Disclosed 2026-10-04Updated 2026-10-04Tokyo[Contained][Severity: Major]
Nikkei: Microsoft 365 account takeover sends about 9,000 spoofed emails[Credential abuse][Phishing][Data leak]Leaked 26Organizations 2Disclosed 2026-10-03Updated 2026-10-09Mie, Tokyo[Resolved][Severity: Major]
Recruit: StudySapuri flaw reveals registered email addresses[Web app exploit][Data leak]Leaked 3.7KOrganizations 3Disclosed 2026-10-02Updated 2026-10-23Tokyo[Investigating][Severity: Major]
Abahouse International: member and order data intrusion[Intrusion][Data leak][Fraud]Organizations 1Disclosed 2026-10-02Updated 2026-10-23Tokyo[Investigating][Severity: Major]
JOGMEC: unauthorized access to its information systems[Intrusion][Data leak]Leaked 7.4KOrganizations 1Disclosed 2026-10-02Updated 2026-10-16Tokyo[Resolved][Severity: Critical]
Sammy Networks: unauthorized access to 777CON-PASS[API abuse][Data leak]Leaked 2.2MOrganizations 1Disclosed 2026-10-02Updated 2026-10-16Tokyo[Investigating][Severity: Major]
Japan Times: ransomware on the group's former administrative server[Ransomware][Data leak]Organizations 2Disclosed 2026-10-02Updated 2026-10-05Tokyo[Resolved][Severity: Major]
National Tax Agency: e-Tax data exposure[Misconfiguration][Data leak]Leaked 203Organizations 1Disclosed 2026-10-02Updated 2026-10-05Tokyo[Contained][Severity: Major]
Kodansha BECK: employee email account intrusion[Credential abuse][Data leak]Organizations 1Disclosed 2026-10-02Updated 2026-10-02Tokyo[Investigating][Severity: Critical]
Daiichi Life Group: unauthorized access to the HR system[Intrusion][Data leak]Leaked 120KOrganizations 2Disclosed 2026-10-02Updated 2026-10-02Tokyo[Resolved][Severity: Critical]
Nichii Gakkan: care services site backup exposed[Misconfiguration][Data leak]Leaked 583Organizations 1Disclosed 2026-10-01Updated 2026-10-01 15:18Tokyo[Contained][Severity: Critical]
Lashinbang: unauthorized access to its services[Intrusion][Data leak]Organizations 1Disclosed 2026-10-01Updated 2026-10-01Tokyo[Resolved][Severity: Major]
Daimaru Matsuzakaya Department Stores: other members' details displayed[Unknown][Data leak]Leaked 581Organizations 1Disclosed 2026-10-01Updated 2026-10-01Tokyo[Contained][Severity: Major]
Nippon Rent-A-Car: separate attack on its app[Intrusion][Data leak]Leaked 55Organizations 1Disclosed 2026-10-01Updated 2026-10-01Tokyo[Resolved][Severity: Major]
Ticketplus: Tickeplus displays other users' data[Misconfiguration][Data leak][Service outage]Leaked 107Organizations 1Disclosed 2026-09-30Updated 2026-10-29Akita, Hiroshima, Kyoto, Tokyo[Investigating][Severity: Critical]
Sagawa: parcel tracking service intrusion[Intrusion][Data leak][Service outage]Leaked 53.2MOrganizations 5Disclosed 2026-09-30Updated 2026-10-01Tokyo[Investigating][Severity: Critical]
G-Plan: unauthorized access to the G-Point system[Intrusion][Data leak][Service outage]Leaked 70KOrganizations 1Disclosed 2026-09-30Updated 2026-09-30Tokyo[Contained][Severity: Major]
Benefit One: survey downloads expose other companies' staff data[Misconfiguration][Data leak]Leaked 13.5KOrganizations 1Disclosed 2026-09-29Updated 2026-10-16Tokyo[Contained][Severity: Critical]
Yamato Transport: Kuroneko deferred payment intrusion[Intrusion][Data leak]Leaked 5.3MOrganizations 4,100