FreeBSD Security Advisory FreeBSD-SA-03:09.signal – Systems with the device driver spigot added into the kernel configuration are susceptible to a denial of service attack due to improper validation of signal numbers.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/31526/FreeBSD-SA-03%3A09.signal
Source: https://packetstormsecurity.com/files/31526/FreeBSD-Security-Advisory-2003.9.html