SLeak confirmedJanuary 30, 2026 announced

静岡市Data breach / unauthorized access incident

Reviewed by Yutaro SasaoWritten by Leak Watch editorial teamJanuary 30, 2026 published ・ October 20, 2026 updated

Occurred on: December 2, 2025
Announced on: January 30, 2026
Severity: SCompromise of deep personal data or usable credentials.
Scale: 3,950 people
Main impact: Materials containing names, addresses, and phone numbers of 3,950 welfare recipients etc. were leaked; some materials included sensitive information such as My Number and disease names, and personal information of two depot employees was also disclosed.
Information involved: Full nameHome addressPhone numberUser / member IDHealth & medical data
Cause / key point: Physical loss/leak caused by an employee leaving a bag containing documents with personal information of welfare recipients etc. on a train, which was retrieved by someone else.
Industry: Government & municipal
Listing / capital: Government / public body
Incident involving a local government
Sources: 静岡市（2026-01-30）
Last updated: October 20, 2026

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Written & reviewed

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: October 20, 2026

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: Loss & theft(Physical loss of devices and media)

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