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JAENES
SPossible leakSeptember 10, 2026 announced

さくらインターネット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
September 10, 2026
Severity
SCompromise of deep personal data or usable credentials.
Scale
1,360,000 accounts
Main impact
Data for 約136万アカウント including member and contract information and some initial server passwords and VPS administrator initial passwords may have been viewed or obtained. It was also announced that names and email addresses of third-party organizations storing data on さくらのレンタルサーバ (e.g., 一般社団法人セーファーインターネット協会) and contents of reports/inquiries may have been viewed or obtained by third parties; no misuse or secondary damage of these third-party-held data has been confirmed to date.
Information involved
Email addressUser / member IDPasswordPhone numberHome addressFull nameDate of birth
Cause / key point
Unauthorized access by a third party to our service (さくらのレンタルサーバ) may have resulted in viewing or obtaining data stored on the service.
Sources
Last updated
October 21, 2026
Email addressUser / member IDPasswordPhone numberHome addressFull nameDate of birthHow 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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