株式会社じほうData breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- February 26, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- 890 records
- Main impact
- An unauthorized login to a specific cloud mail account resulted in phishing emails being sent to entries in the address book; it was disclosed that 890 email addresses were affected.
- Information involved
- Email address
- Cause / key point
- An unauthorized login to a cloud mail account caused messages to be sent via the account's address book.About Targeted email & phishing
- Industry
- Services & other
- 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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Attack method classification: Targeted email & phishing(Fake emails and sites that steal credentials)
Read the Targeted email & phishing guide and national trends →