The kernel in NetBSD-current before September 28, 2005 allows local users to cause a denial of service (system crash) by using the SIOCGIFALIAS ioctl to gather information on a non-existent alias of a network interface, which causes a NULL pointer dereference.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25766
http://www.securityfocus.com/bid/17497
http://securitytracker.com/id?1015908
http://secunia.com/advisories/19615
http://archives.neohapsis.com/archives/netbsd/2006-q2/0014.html