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JAENES
ALeak confirmedOctober 6, 2026 announced

長崎市（特別徴収税額変更通知の誤送付）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
September 17, 2026
Announced on
October 6, 2026
Severity
AFinancial and HR records — information that easily translates into monetary damage.
Scale
1 people
Main impact
A notice of change in special collection tax amount was mistakenly sent to another business, resulting in one person's address, name, tax amount, etc. being disclosed externally.
Information involved
Home addressFull name
Cause / key point
The cause is under investigation.
Industry
Government & municipal
Listing / capital
Government / public body
Sources
Last updated
October 20, 2026
Home 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: Misdirected sending & disclosure (human error)(Leaks caused by wrong recipients or exposure settings)

Read the Misdirected sending & disclosure (human error) guide and national trends →

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