cota-2026 · Disclosed 2026-03-30

コタ: unauthorized access and impact

Investigation of PC malfunctions on March 27 identified unauthorized access; the entry route is undisclosed. Eight datasets total 109,147 potentially affected records; investigation did not confirm leakage but could not rule it out.

Cause unresolved / undisclosed

Outcome: Confirmed breach

Entry path and evidence

Reported fact
Investigation of PC malfunctions on March 27 identified unauthorized access; the entry route is undisclosed.
[s1]pp.1-2 §§1,2,4
Reported fact
Eight datasets total 109,147 potentially affected records; investigation did not confirm leakage but could not rule it out.
[s1]pp.1-2 §§1,2,4

Timeline

2026-03-30
Disclosure date established by the reviewed notice. [s1]

Reported response

Reported fact
All servers and PCs were disconnected while specialists investigated and restored systems.
[s1]pp.1-2 §§1,2,4

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

AI involvementUnknown

The reviewed disclosures do not establish attacker use of AI.

The cumulative record total spans eight datasets; overlap and actual exfiltration remain unresolved.

Sources

[s1] コタ · Primary source
コタ：事故に関する公表資料 ↗
Reviewed 2026-10-09