SHINDO2

Osaka City Public Health Center

Osaka City

Email addresses111records

LEAK CONFIRMEDMisdelivery · Closed (final report)

Open in the live monitor ▶
Disclosed
Jun 4, 2026
Leak
Leak confirmed
Type
Misdelivery
Status
Closed (final report)
Security spend
Not checked yet
Compensation
Not announced

What leaked

ContactEmail address

How many

  • Email addresses 111 records
  • Personal email addresses 57 records

Who is affected

  • Medical institutions planning to apply for a subsidy

Cause

Addresses meant for BCC were put in the To field

Timeline

  1. Exposure began
  2. First disclosure

Response

  • Data deleted
  • Notified individuals
  • Change process

Phoned the institutions to apologize and ask for deletion; BCC and double checks enforced

What you should do

  1. Don't open links in emails from this company. The apology email itself may be fake
  2. Check the company's notice to see if you're affected

Lessons for companies

  1. Use DLP: recipient checks, send delay, automatic attachment protection
  2. Report to the PPC: preliminary in 3–5 days, final in 30 (60 if malicious)
  3. Run red teaming and AI-assisted hardening, and publish how much you invest

Sources