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

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

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