The nullfs implementation in sys/fs/nullfs/null_vnops.c in the kernel in FreeBSD 8.3 through 9.2 allows local users with certain permissions to bypass access restrictions via a hardlink in a nullfs instance to a file in a different instance.
Category : Permissions, Privileges, and Access Controls Weaknesses in this category are related to the management of permissions, privileges, and other security features that are used to perform access control.