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JAENES
BLeak confirmedSeptember 24, 2026 announced

大阪市立美術館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 10, 2026
Announced on
September 24, 2026
Severity
BIncidents centered on names and contact details.
Scale
30 people
Main impact
It was confirmed that an email was mistakenly sent in a state where 30 course participants could mutually view each other’s names and email addresses.
Information involved
Email addressFull name
Cause / key point
The person in charge misentered a group email address into the recipient field and did not perform a reconfirmation before sending.
Industry
Government & municipal
Listing / capital
Government / public body

A public art museum of 大阪市

Sources
Last updated
October 20, 2026
Email addressFull nameHow 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)

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