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JAENES
BPossible leakApril 8, 2026 announced

エフワンData breach / unauthorized access incident

笹尾 祐太朗の写真Reviewed by Yutaro SasaoWritten by Leak Watch editorial team published ・ updated
Occurred on
January 26, 2026
Announced on
April 8, 2026
Severity
BIncidents centered on names and contact details.
Scale
170,000 records
Main impact
It was determined that about 170,000 personal information records were leaked in a ransomware attack, and the names, employers, etc. of 131 customers of business partners may also be affected.
Information involved
Full name
Cause / key point
An unauthorized remote desktop connection via VPN, believed to have exploited a security hole in equipment used for backup lines.About Ransomware
Industry
Retail & e-commerce
Listing / capital
Unlisted
Sources
Last updated
October 20, 2026
Full nameHow severity is assessed →

Is this incident worth paying attention to?

Written & reviewed

笹尾 祐太朗の写真

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: Ransomware(Encrypting data and demanding a ransom)

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