The NFS server (nfsserver) in FreeBSD 8.3 through 10.0 does not acquire locks in the proper order when converting a directory file handle to a vnode, which allows remote authenticated users to cause a denial of service (deadlock) via vectors involving a thread that uses the correct locking order.
http://secunia.com/advisories/57760
http://secunia.com/advisories/59034
http://www.debian.org/security/2014/dsa-2952
http://www.freebsd.org/security/advisories/FreeBSD-SA-14:05.nfsserver.asc