SHINDO3

Osaka Kyoiku University

Email addresses2,376records

LEAK CONFIRMEDMisdelivery · Closed (final report)

Open in the live monitor ▶
Disclosed
Feb 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 2,376 records

Who is affected

  • Students

Cause

Recipients were put in the To field by mistake, so addresses were visible to all

Timeline

  1. First mis-send
  2. Second mis-send
  3. First disclosure

Response

  • Data deleted
  • Notified individuals

Apologized to students and asked them to delete the emails

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