総務省Data breach / unauthorized access incident
- Occurred on
- Unconfirmed
- Announced on
- October 9, 2026
- Severity
- BIncidents centered on names and contact details.
- Scale
- Unknown
- Main impact
- An advisory urging operators that handle large volumes of personal data to strengthen measures, calling for rapid vulnerability remediation and the introduction of multi-factor authentication, after repeated unauthorized accesses to their information systems and confirmed thefts of data including personal information.
- Information involved
- Not specified in the disclosure
- Cause / key point
- Advisory issued because multiple incidents were confirmed in which attackers gained unauthorized access to information systems and stole data that included personal information.About Exploitation of vulnerabilities
- Industry
- Government & municipal
- Listing / capital
- Government / public body
- Last updated
- October 23, 2026
Is this incident worth paying attention to?
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:
Written by:Leak Watch editorial team (AI-assisted drafts verified against sources by the editorial team) · Reviewer profile · Request a correction
Related incidents
Browse the database →Incidents sharing the same company, service, attack method or industry (grouped automatically from the disclosures).
Same attack method
- SSHelpfeel（Gyazo）2026.09.16 announced・Affected 23,620,000 records
- SSEストアー(ショップサーブ)2026.10.16 announced・Affected 23,356,000 people
- SSSアドベンチャー（スカイチケット）2026.10.10 announced・Affected 14,640,000 records
- SSSKDDI(ISP事業者向けメール基盤)2026.06.23 announced・Affected 12,231,954 people
- Sムラウチドットコム2026.09.15 announced・Affected 7,710,000 records
- Sホワイトエッセンス（予約・基幹システム）2026.10.05 announced・Affected 1,050,000 accounts
Same industry
- S市立岸和田市民病院（患者書類）2026.10.16 announced・Affected 1 people
- S大崎地域広域行政事務組合消防本部（NET119・119RAIDEN）2026.10.14 announced・Affected 45 people
- S神奈川県警（使用済み運転免許証）2026.10.09 announced・Affected 30 records
- S長崎市（マイナンバーカード特急発行書類の紛失）2026.09.08 announced・Affected 4 people
- S村田製作所2026.04.27 announced・Affected 73,000 records
- S静岡市2026.01.30 announced・Affected 3,950 people
Attack method classification: Exploitation of vulnerabilities(Breaking in through holes in software and devices)
Read the Exploitation of vulnerabilities guide and national trends →