There exists an authentication bypass vulnerability in OpenThread border router devices and implementations. This issue allows unauthenticated nodes to craft radio frames using “Key ID Mode 2”: a special mode using a static encryption key to bypass security checks, resulting in arbitrary IP packets being allowed on the Thread network. This provides a pathway for an attacker to send/receive arbitrary IPv6 packets to devices on the LAN, potentially exploiting them if they lack additional authentication or contain any network vulnerabilities that would normally be mitigated by the home router’s NAT firewall. Effected devices have been mitigated through an automatic update beyond the affected range.