CAC（Academic Support Navi）Data breach / unauthorized access incident
- Occurred on
- December 18, 2025
- Announced on
- March 23, 2026
- Severity
- SCompromise of deep personal data or usable credentials.
- Scale
- Unknown
- Main impact
- Unauthorized access to "Academic Support Navi" caused the service to be suspended for about 3 months; resumption is being carried out sequentially from 2026-03-23. A data leak is indicated as a possibility.
- Information involved
- Email addressHome addressFull nameDate of birth
- Cause / key point
- Unauthorized access to the service led to a prolonged suspension.
- Industry
- IT & telecom
- Listing / capital
- Listed company東証プライム 4725(CAC Holdings)
The listed company is CAC Holdings
- Last updated
- October 20, 2026
Stock price reaction to the disclosureCAC Holdings / 東証プライム 4725
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Written & reviewed
Reviewed byYutaro SasaoFounder & CEO, MediaLeap Inc.
CEO of MediaLeap Inc. Working on both sides of web advertising and web media since 2013; founded the company in May 2025.
Review scope: cross-checking against primary sources (official and government announcements), verifying claims stay within the facts, and checking source attribution。Last reviewed:
Written by:Leak Watch editorial team (AI-assisted drafts verified against sources by the editorial team) · Reviewer profile · Request a correction
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Attack method classification: Unauthorized access (method undisclosed)(Breached, but the technique was not identified or disclosed)
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