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JAENES
BPossible leakOctober 31, 2026 announced

西日本旅客鉄道（JR西日本）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
October 30, 2026
Announced on
October 31, 2026
Severity
BIncidents centered on names and contact details.
Scale
2 records
Main impact
Personal data for two purchasers of the 80th unsecured corporate bonds may have been taken out by unauthorized third-party access. The leaked items are name, address, phone number, email address, gender, and date of birth.
Information involved
Full nameHome addressPhone numberEmail addressDate of birth
Cause / key point
Possible data exfiltration due to unauthorized third-party access to a SaaS (digital securities platform) provided by a contractor of NTTデータ.About Supply chain attacks (via vendors & shared services)
Industry
Transport & travel
Listing / capital
Listed company
Sources
Last updated
November 3, 2026

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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: Supply chain attacks (via vendors & shared services)(Compromising the provider instead of the user)

Read the Supply chain attacks (via vendors & shared services) guide and national trends →

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