FreeBSD Security Advisory – Due to a missing length check in the code that handles DNS parameters, a malformed router advertisement message can result in a stack buffer overflow in rtsold(8). Receipt of a router advertisement message with a malformed DNSSL option, for instance from a compromised host on the same network, can cause rtsold(8) to crash. While it is theoretically possible to inject code into rtsold(8) through malformed router advertisement messages, it is normally compiled with stack protection enabled, rendering such an attack extremely difficult. When rtsold(8) crashes, the existing DNS configuration will remain in force, and the kernel will continue to receive and process periodic router advertisements.