FreeBSD contains a flaw that may allow a local denial of service. The issue is triggered when a malicious user calls mmap() to map the memory address of its own mem file the procfs filesystem causing the kernel to go into an infinite loop, and will result in loss of availability for the platform.
Upgrade to version 3.5.1-STABLE or 4.2-STABLE dated after the correction date or higher, as it has been reported to fix this vulnerability. It is also possible to correct the flaw by implementing the following workaround: unmount all instances of the procfs filesystem.
#umount -f -a -t procfs
Disable automatic mounting of procfs in /etc/fstab:
#proc /proc procfs rw 0 0