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JAENES
BLeak confirmedSeptember 8, 2026 announced

京都サンガF.C.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 2, 2026
Announced on
September 8, 2026
Severity
BIncidents centered on names and contact details.
Scale
15,612 people
Main impact
Due to an erroneous transmission to a business partner, fan club member information for 15,612 people (name, address, date of birth, etc.) was sent; the recipient confirmed deletion on the same day.
Information involved
Home addressFull nameDate of birth
Cause / key point
The fan club member information file was mistakenly attached to an email addressed to a client company.
Industry
Services & other
Listing / capital
Unlisted
Sources
Last updated
October 20, 2026
Home addressFull nameDate of birthHow severity is assessed →

Is this incident worth paying attention to?

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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