Company

Japan Post Co., Ltd.

Japan Post Co., Ltd. (Chiyoda, Tokyo; Transport and postal services) appears in 3 related cybersecurity incidents. The latest was disclosed on 2026-09-29.

Profile

Industry/type

Transport and postal services

Location

Tokyo, Chiyoda

Services

Post Office App

Website

https://www.post.japanpost.jp/

Parent

Japan Post Holdings Co., Ltd.since 2007-10-01

Public figures

–

Metric	Value		As of	Source
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Incident history

Disclosed 2026-09-29Updated 2026-10-22Tokyo[Contained][Severity: Major][Breached][Major]
Japan Post: unauthorized access to the Post Office App
[Intrusion][Data leak][Service outage]Leaked 69Organizations 1
Disclosed 2026-09-25Updated 2026-10-23Tokyo[Contained][Severity: Major][Breached][Major]
Japan Post: unauthorized access to the web service for international mail inquiries
[Intrusion][Data leak]Leaked 600Organizations 1
Disclosed 2020-02-14Updated 2020-02-18 10:00Tokyo[Resolved][Severity: Moderate][Breached][Moderate]
Japan Post: unauthorized access to one of its mail domains sent about 4,000 unwanted emails
[Intrusion]Organizations 1

		Incident	Role	Impact level				Methods	Impacts		Status
2026-09-29	2026-10-22	Japan Post: unauthorized access to the Post Office App	[Breached]	[Major]	[Major]	1 Japan Post Co., Ltd.	Tokyo	[Intrusion]	[Data leak][Service outage]	69	[Contained]
2026-09-25	2026-10-23	Japan Post: unauthorized access to the web service for international mail inquiries	[Breached]	[Major]	[Major]	1 Japan Post Co., Ltd.	Tokyo	[Intrusion]	[Data leak]	600	[Contained]
2020-02-14	2020-02-18 10:00	Japan Post: unauthorized access to one of its mail domains sent about 4,000 unwanted emails	[Breached]	[Moderate]	[Moderate]	1 Japan Post Co., Ltd.	Tokyo	[Intrusion]		Unknown	[Resolved]