The nl_fib_input function in fib_frontend.c in the Linux kernel before 2.6.15 does not check for valid lengths of the header and payload, which allows remote attackers to cause a denial of service (invalid memory reference) via malformed fib_lookup netlink messages.
http://www.vupen.com/english/advisories/2006/0035
http://www.securityfocus.com/bid/16139
http://www.novell.com/linux/security/advisories/2006_06_kernel.html
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.15