Using portsuprade only for security

[Daniel Underwood]

I ran a portsupgrade scan, and was presented with a long list of
installed ports and whether an update was available. In general, I
prefer not to update ports/packages between FreeBSD releases. An
obvious exception to this general rules is the patching of security
vulnerabilities; of course not all available updates are security
fixes.

So my question is: how or where can I monitor security
vulnerabilities? Or, how can I keep my system up-to-date with respect
to security, without applying every non-security update?

Thanks,
Daniel