glsa-check
glsa-check… securitity in gentoo
what is glsa-check - you can find here http://gentoo-wiki.com/Glsa-check
why to use it - because it shows every possible security hole made by outdated software. Because the output of glsa-check is rather chatty - my own grep method is like this:
glsa-check -d affected |grep -e “Affected package”