Occasionally you might try to do a make on a ports package and you might get an error telling you that the package you have selected has known vulnerabilities and it will ask you to update your ports collection before trying the build again.
In an idealistic world, this makes perfect sense, and you simply update your ports collection (i.e. run portsnap fetch and portsnap update).
The real world is far from idealistic, and at times this becomes impossible. For example, I have a server in an environment where ports is NFS mounted among multiple machines, prohibiting this machine from actually updating ports.
A quick solution in a bind is to simply disable the vulnerability checking while building:
# make -DDISABLE_VULNERABILITIES
Alternately, you can set the environment varible DISABLE_VULNERABILITIES to yes. This is most specificly useful if you have dependencies which will also fail vulnerability checking. In bash, you can do so by the following:
# export DISABLE_VULNERABILITIES=yes
Now you should be able to finish building and perform a make install as usual.