2026 Keio Corporation — ransomware; hospitality systems disrupted (PII census pending)
Data compromised
Company investigating whether customer or business-partner information was accessed. Public reporting points to hospitality / payment-system disruption (Keio Plaza Hotel); train operations not reported as affected. No attested PII census at indexing — recordsAffected 0.
Technical writeup
Verified company notice — Keio Corporation confirmed a ransomware attack on group servers in the early hours of September 26, 2026, reported to police, and shut systems to contain damage. Hospitality-side customer services (Keio Plaza Hotel) warned of delays; local press cited payment-system disruption. No ransomware group claim identified by trade press at indexing; customer/partner data access still under investigation with external experts. recordsAffected 0 until a census is published; companyConfirmed true.
Root cause
Ransomware on group servers confirmed early hours of September 26, 2026 (Keio notice); network shut down.