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JAENES
ALeak confirmedOctober 21, 2026 announced

ラクスライトクラウド（ブラストメール）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
October 21, 2026
Severity
AFinancial and HR records — information that easily translates into monetary damage.
Scale
Unknown
Main impact
An external third party accessed two API servers for the email delivery service "ブラストメール", executed commands, connected to the sales management system and service database, and it was confirmed that data was exfiltrated. The exfiltrated data includes company names, contact person names, phone numbers, email addresses, billing email addresses, contract and payment histories for all subscribers, and for some subscribers also email distribution-related information such as recipient lists; credit card numbers are not retained and therefore were not exposed. Services were suspended from 2026-10-21 0:30 to prevent further damage, and the recovery time is undecided; the intrusion route is under investigation.
Information involved
Full namePhone numberEmail address
Cause / key point
Unauthorized intrusion by an external third party into API servers and data exfiltration via connections between systems (intrusion route under investigation).About Supply chain attacks (via vendors & shared services)
Industry
IT & telecom
Listing / capital
UnlistedParent company (listed on TSE Prime).: 株式会社ラクス(東証プライム 3923.T)
Sources
Last updated
October 23, 2026

Stock price reaction to the disclosure株式会社ラクス・親会社（東証プライム上場） / 東証プライム 3923.T

2026.10.01 〜 2026.10.23Loading…

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Where to go for this information

The steps themselves are on the protection guide. These links match the kinds of data in this incident, plus support contacts.

Full namePhone numberEmail addressHow 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: 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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