The (1) IPv6 and (2) ATM ioctl request handlers in the kernel in FreeBSD 8.3 through 9.2-STABLE do not validate SIOCSIFADDR, SIOCSIFBRDADDR, SIOCSIFDSTADDR, and SIOCSIFNETMASK requests, which allows local users to perform link-layer actions, cause a denial of service (panic), or possibly gain privileges via a crafted application.
http://www.freebsd.org/security/advisories/FreeBSD-SA-13:12.ifioctl.asc
http://www.debian.org/security/2013/dsa-2769
http://svnweb.freebsd.org/base?view=revision&revision=255442