osaka-high-court-teams-2026 · Disclosed First disclosure unknown
大阪高等裁判所: data exposure and authorization boundaries
A case-specific Teams group mistakenly included unintended members; no external intrusion was reported. Approximately 3,500 external and 2,500 staff accounts could see each other’s names and email addresses; case records were unaffected.
Outcome: Exposure / potential leak. Third-party theft unconfirmed.
Entry path and evidence
Timeline
Event date reported by the source. [s1]
Reported response
- Reported fact
The team was deleted immediately after an external inquiry.
[s1]本文 第1-2段落
Evidence relevant to prevention
Operational controls to inspect
Inspect the disclosed configuration, authorization or operational issue. Verify applicability and retain evidence of behavior after remediation.
Editorial assessment; not a determination of liability. [s1]
Unknowns and AI involvement
The reviewed disclosures do not establish attacker use of AI.
The publication date is not stated in the notice body.
Sources
[s1] 大阪高等裁判所 · Primary source
大阪高等裁判所：事故に関する公表資料 ↗Reviewed 2026-10-09