マイナビ（利用クラウド）Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- March 31, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 74,224 records
- Main impact
- There is a risk of leakage of names, emails, addresses, etc. for 74,224 general users, 21,609 corporate contacts, and 15,672 employees. Card numbers and My Number (national ID) are reported not to be included.
- Information involved
- Email addressPhone numberHome addressFull name
- Cause / key point
- Unauthorized access to the cloud service used that bypassed normal security measures.
- Industry
- IT & telecom
- Listing / capital
- Unlisted
- Last updated
- October 20, 2026
Is this incident worth paying attention to?
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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Same industry
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Attack method classification: Unauthorized access (method undisclosed)(Breached, but the technique was not identified or disclosed)
Read the Unauthorized access (method undisclosed) guide and national trends →