Honjo warns of possible card appointment data leak following subcontractor breach
SpilloverSpillover from the Arara incident · View original incident →Unauthorised access took place between 28 and 31 October 2026 on arara message, a service run by arara, to which TKC, the contractor for Honjo’s My Number Card issuance appointment and management system, had subcontracted email delivery. Registered email addresses, names and other information may have been leaked, and whether any Honjo-related information was leaked and the extent of any such leak are still being investigated. In a follow-up notice on 10 November, the city said it had moved to a new email infrastructure and resumed sending appointment confirmation emails.
Key facts
- Affected organisation
- City of Honjo
- Original incident
- Arara email service cyber-attack exposes 81.33 million email addresses
- Incident type
- Data breach
- Occurred / detected
- 2026-10-28
- Scale of damage
- Possible personal information leak
- Cause / method
- Unauthorised access involving the contractor for the My Number Card issuance appointment and management 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
- Honjo published its first follow-up notice on a possible personal information leak resulting from unauthorised access involving the system contractor.
Original incident
This is spillover from the Arara incident.
Arara email service cyber-attack exposes 81.33 million email addresses
81.3mImpact: 81,329,467 email addresses and some customers' member information
Japan's Arara Message email delivery service was breached through a web server vulnerability, exposing email addresses and some customers' member information. Further investigation put the number of unique email addresses exposed at 81,329,467. The attacker also misused the service to send up to approximately 7.13 million emails impersonating credit card companies, and the company isolated the servers and suspended its email delivery service entirely.
Related reports: 20 · last report →
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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.