Higashiosaka: application users’ emails at risk after mail-supplier intrusion
Its application provider’s mail supplier was breached. User-email exposure and count are being checked; registration and some account changes are suspended.
Disclosed
2026-11-04
Organizations involved
1
Leaked or at risk
Unknown
Downtime
Unknown
Published findings and remaining uncertainty
The external mail service used by its application-system provider suffered unauthorized access. User email addresses may have leaked; actual inclusion and count remain under investigation. Registration, email changes and password resets are unavailable, while other functions remain usable; no restoration date is given. Neither provider is named, so TKC/Arara attribution is unconfirmed. The page’s 1 October 2021 publication label is the original page date, not this incident’s date; the cited incident notice is the version updated on 4 November 2026. [1]
Timeline
- Disclosed 2026-11-04
- 1 days
Attack or cause
- Method
- [Intrusion]
- Impact
- [Data leak][Service outage]
- Entry point
- Unknown
Data exposed or at risk
Supply chain
Services hit
Organizations involved
[Through a supplier][Major]Osaka, HigashiosakaMunicipality
Higashiosaka City
Sources
- [1][Official]東大阪市電子申請システムでの情報漏えいのおそれについてHigashiosaka City · 2026-11-04