> JapanHacked_
[Investigating][Severity: Major][Intrusion]

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

  1. Disclosed 2026-11-04
  2. 1 days

Attack or cause

Method
[Intrusion]
Impact
[Data leak][Service outage]
Entry point
Unknown

Data exposed or at risk

[E-mail address]

Supply chain

Organizations listed on this site
1

Services hit

Organizations involved

Sources

  1. [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