The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whether the rewritten data fit in the buffer, or whether the result fit back in the original pa…

Summary

The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whether the rewritten data fit in the buffer, or whether the result fit back in the original packet. A host sending crafted RTSP traffic from inside a NAT gateway using libalias can overflow a stack buffer, potentially achieving remote code execution in the kernel (when using ipfw(4) NAT) or in the natd(8) process (which generally runs as the root user).