The nand_ioctl function in sys/dev/nand/nand_geom.c in the nand driver in the kernel in FreeBSD 10 and earlier does not properly initialize a certain data structure, which allows local users to obtain sensitive information from kernel memory via a crafted ioctl call.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2013-6634
http://archives.neohapsis.com/archives/fulldisclosure/2013-11/0106.html