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.

767 results
Confirmed

JIHS: lost cardiac-exam HDD left data on 83,007 patients unaccounted for

An HDD removed for disposal from a cardiac exam device and stored in a locked warehouse was found missing on April 16, 2026 and remains unfound. It held exam data from Dec 1998–Dec 2023. Disclosed July 31. No confirmed external leak or misuse.

Investigating

Meitetsu Kyosho: customer data may have leaked after server intrusion

Possible data leak: Unauthorized server access noticed June 23, 2026. Attacks on multiple servers were confirmed and external leakage of customer data could not be ruled out; disclosed July 28 (following a July 2 outage notice). Headcount still under investigation.