埼玉県（渋沢MIX）Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 7, 2026
- Severity
- AFinancial and HR records — information that easily translates into monetary damage.
- Scale
- 2,200 people
- Main impact
- A list containing names, emails, etc. of approximately 2,200 people was accessed without authorization, and detailed information for 3 of them was also accessed. Alteration of registration data and unauthorized email sending have also been confirmed.
- Information involved
- Email addressFull name
- Cause / key point
- It is believed a vulnerability in the management system handling member information and facility reservations was exploited, but details are under investigation.About Exploitation of vulnerabilities
- Industry
- Government & municipal
- Listing / capital
- Government / public body
Municipality (埼玉県)
- Last updated
- October 20, 2026
Is this incident worth paying attention to?
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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: Exploitation of vulnerabilities(Breaking in through holes in software and devices)
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