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JAENES
BPossible leakAugust 10, 2026 announced

五大開発株式会社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
Unconfirmed
Announced on
August 10, 2026
Severity
BIncidents centered on names and contact details.
Scale
Unknown
Main impact
The いさぼうネット server suffered unauthorized access and member information may have been leaked; after confirming the attack on January 26 they stopped and isolated the server and announced migration to a new environment.
Information involved
Email addressPasswordPhone numberHome addressFull name
Cause / key point
They state that unauthorized access to the server may have resulted in leakage of member information.
Industry
Real estate
Listing / capital
Unlisted
Sources
Last updated
October 20, 2026
Email addressPasswordPhone numberHome addressFull nameHow severity is assessed →

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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: Unauthorized access (method undisclosed)(Breached, but the technique was not identified or disclosed)

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