Say what you will of +Dan Kaminsky
, but he is one of the brightest minds on the subject of the Domain Name System, which is a key part of the recent glibc exploit (CVE-2015-7547). He's among a group of people working to really wrap their brains around the scope of this bug.
This is a good read.
The illustration here is a map of Ubuntu's dependencies. The map will be similar for pretty much any GNU/Linux distribution, though. The single black pixel at the middle of it all is systemd. Haha I'm just kidding it's glibc but systemd and almost everything else on GNU/Linux relies on glibc in some way.