Mizuho Leasing: unauthorized access to a power investment system
Mizuho Leasing confirmed on 14 December 2025 that part of its systems had been accessed without authorization and disclosed it on 6 January. The system handles power generation investments and runs on separate external infrastructure from the core systems; it was cut off. At disclosure no business impact or data leak had been confirmed.
Disclosed
2026-01-06
Organizations involved
1
Leaked or at risk
Unknown
Downtime
Unknown
Timeline
- Detected 2025-12-14
- Disclosed 2026-01-06
- 23 days
Attack or cause
- Method
- [Unknown]
- Impact
- Entry point
- Unknown
Data exposed or at risk
–
Organizations involved
[Breached][Moderate]Tokyo, MinatoReal estate and rental
Mizuho Leasing Company, Limited
Sources
- [1][Official]当社システムに対する不正アクセスについてMizuho Leasing · 2026-01-06