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 2026-03-24Updated 2026-04-07 08:05Tokyo[Contained][Severity: Moderate]
MLIT and Hakuhodo: Eco-Home Support mail server abused[Intrusion]Organizations 2Disclosed 2026-03-18Updated 2026-03-23 08:05Tokyo[Contained][Severity: Major]
NHK: email address disclosure[Misdelivery][Data leak]Leaked 32.9KOrganizations 1Disclosed 2026-03-17Updated 2026-07-27 08:05Fukuoka, Osaka, Saitama, Tokyo[Contained][Severity: Major]
Nippon Telenet: ransomware-type attack encrypts server files[Ransomware][Data leak][Service outage]Organizations 5Disclosed 2026-03-06Updated 2026-07-10Kanagawa, Tokyo[Resolved][Severity: Moderate]
Seed Planning: ransomware attack[Ransomware][Service outage]Leaked 130KOrganizations 4Disclosed 2026-03-06Updated 2026-03-18 08:05Tokyo[Resolved][Severity: Moderate]
PGF Life: agency secondees improperly take information[Insider][Data leak]Leaked 379Organizations 1Disclosed 2026-02-19Updated 2026-10-07Tokyo[Contained][Severity: Major]
Advantest: ransomware attack[Ransomware][Intrusion][Data leak][Service outage]Organizations 1Disclosed 2026-02-13Updated 2026-04-23Tokyo[Contained][Severity: Critical]
BEENOS: Sekaimon intrusion[Web app exploit][Data leak][Service outage]Organizations 1Disclosed 2026-02-12Updated 2026-05-13Tokyo[Resolved][Severity: Major]
Ficha: ransomware attack on its servers[Ransomware][Data leak]Organizations 1Disclosed 2026-02-12Updated 2026-03-31Tokyo[Contained][Severity: Major]
Mynavi: unauthorized access to a cloud service it uses[Unknown][Data leak]Leaked 74.2KOrganizations 1Disclosed 2026-02-12Updated 2026-03-04 08:05Tokyo[Resolved][Severity: Moderate]
Dai-ichi Life Group: agency secondees improperly obtain data[Insider][Data leak]Organizations 1Disclosed 2026-02-10Updated 2026-03-09 08:05Tokyo[Investigating][Severity: Moderate]
Japan Airlines: contractor log changes disrupt baggage booking[Insider][Service outage]Organizations 1Disclosed 2026-02-05Updated 2026-02-17Tokyo[Contained][Severity: Critical]
At Home: unauthorized login to the moving quote system[Credential abuse][Data leak][Service outage]Leaked 5.1KOrganizations 1Disclosed 2026-01-30Updated 2026-02-19 08:05Tokyo[Resolved][Severity: Moderate]
MC Retail Energy: Machi-ene supplier server attack[Unknown][Service outage]Organizations 1Disclosed 2026-01-27Updated 2026-02-16 08:05Tokyo[Resolved][Severity: Major]
SoftBank: My SoftBank data mix-ups and MMS sender swaps[Misconfiguration][Data leak]Organizations 1Disclosed 2026-01-23Updated 2026-02-12 08:05Tokyo[Contained][Severity: Major]
Ministry of Agriculture, Forestry and Fisheries: email misdelivery[Misdelivery][Data leak]Leaked 4.6KOrganizations 1Disclosed 2026-01-22Updated 2026-02-18Tokyo[Contained][Severity: Major]
Sincere: ransomware attack[Ransomware][Service outage][Data leak]Organizations 1Disclosed 2026-01-06Updated 2026-01-29Tokyo[Resolved][Severity: Major]
CANVASs: ransomware attack on its licensing server[Ransomware][Service outage]Organizations 1Disclosed 2026-01-06Updated 2026-01-06Tokyo[Investigating][Severity: Moderate]
Mizuho Leasing: power investment system intrusion[Unknown]Organizations 1Disclosed 2026-01-05Updated 2026-03-23Tokyo[Resolved][Severity: Major]
CAC: Academic Support Navi intrusion[Credential abuse][Malware][Service outage]Organizations 1Disclosed 2025-12-26Updated 2025-12-26Tokyo[Contained][Severity: Critical]
Keio University: intrusion into the SFC email system[Intrusion][Data leak]Leaked 222.5KOrganizations 1Disclosed 2025-12-25Updated 2026-01-15 08:05Tokyo[Investigating][Severity: Moderate]
WOWOW: My WOWOW unauthorized logins[Credential abuse][Data leak]Organizations 1Disclosed 2025-12-25Updated 2025-12-25Tokyo[Investigating][Severity: Major]
Alcare: work phone account takeover[Phishing][Credential abuse][Data leak]Leaked 400Organizations 1Disclosed 2025-12-24Updated 2026-01-16 08:05Tokyo[Investigating][Severity: Moderate]
SKY Perfect JSAT: browser viewing-site server intrusion[Intrusion]Organizations 1Disclosed 2025-12-23Updated 2025-12-23Tokyo[Contained][Severity: Critical]
FUJIFILM Medical: sales system intrusion[Credential abuse][Data leak]Leaked 590KOrganizations 1Disclosed 2025-12-17Updated 2026-06-16 08:05Tokyo[Investigating][Severity: Moderate]
Omnibus Japan: ransomware at Tohokushinsha group company[Ransomware][Data leak]Organizations 1Disclosed 2025-12-12Updated 2025-12-12Tokyo[Resolved][Severity: Moderate]
Tokyo Hanyaku: website defaced[Intrusion][Site defacement][Service outage]Organizations 1Disclosed 2025-12-08Updated 2025-12-24 08:10Tokyo[Investigating][Severity: Moderate]
TOC: network intrusion[Intrusion]Organizations 1