Ransomware disrupts Cheyenne and Arapaho tribal government and education systems

Beginning on 8 December 2025, a ransomware incident forced the Cheyenne and Arapaho Tribes to take network systems offline and disrupted computers, email, phone services, schools and government operations. Approximately 80% of employee systems at the Concho headquarters had been restored by 2 January 2026, while remaining restoration continued in phases. The Rhysida group later claimed responsibility and demanded 10 bitcoin; the tribe confirmed the ransomware incident but did not independently confirm Rhysida's attribution or alleged data theft.