FreeBSD -- Network ACL mishandling in mountd(8)

Problem Description:
While parsing the exports(5) table, a network mask in the form of
“-network=netname/prefixlength” results in an incorrect network mask
being computed if the prefix length is not a multiple of 8.
For example, specifying the ACL for an export as “-network
192.0.2.0/23” would result in a netmask of 255.255.127.0 being used
instead of the correct netmask of 255.255.254.0.