Japan’s Ota warns of possible personal data leak after October disaster information system breach
Signs of suspected unauthorised access were detected on 11 October 2026 in Arcadia’s information distribution system used by the city of Ota in Gunma Prefecture, Japan. On 15 October, Ota announced that personal information, including the names, email addresses and telephone numbers of people registered for disaster information emails and Net119, may have been leaked. Whether any data had actually leaked or been misused had not been confirmed at the time.
Key facts
- Affected organisation
- City of Ota
- Incident type
- Data breach
- Occurred / detected
- 2026-10-11
- Scale of damage
- Potentially affected service registrants: 27,859 residents and 2,186 staff members registered for disaster information emails, and 42 Net119 registrants. The actual number of people whose data was leaked is unconfirmed.
- Cause / method
- Unauthorised access to the communication system
- Location
- Japan
If your data was exposed
- Don’t tap links in texts, calls or emails that mention this incident and offer compensation, refunds or breach checks. Check directly on the organisation’s official website or app.
Timeline
- Unauthorised access to Ota’s communication system and a possible leak of address information became known.
1 related reports
The summary and key facts are written by AI from related reports and may contain errors. Check the original articles and the organisation’s official statements for accurate details.