daiichi-life-hr-2026 · Disclosed 2026-10-02
第一生命: unauthorized access and impact
Unauthorized access to the employee HR system was detected on September 24. Potential exposure covers about 50,000 employees and 70,000 former employees; customer-data access is unconfirmed.
Outcome: Confirmed breach
Entry path and evidence
Timeline
Disclosure date established by the reviewed notice. [s1]
Reported response
- Reported fact
Former employees were notified of precautions and a dedicated contact channel.
[s1]p.1 冒頭 / 現時点で閲覧され、外部に流出した可能性のある個人情報
Cause and mitigation hypotheses
Not assessed. Editorial hypotheses have not been added for this incident; this does not establish safety or a confirmed cause.
Evidence relevant to prevention
Insufficient evidence
Undisclosed entry or patch timing prevents an avoidability assessment. Inspect privileges, retrieval logs, retention and deployed configuration using the linked rules.
Editorial assessment; not a determination of liability. [s1]
Unknowns and AI involvement
The reviewed disclosures do not establish attacker use of AI.
The entry mechanism and confirmed exfiltration scope are undisclosed.
Sources
[s1] 第一ライフグループ・第一生命 · Primary source
第一ライフグループ・第一生命：事故に関する公表資料 ↗Reviewed 2026-10-09