I just tested my Debian linode after an apt-get clean, update, dist-upgrade, and the test program says it is not vulnerable. The upgrade did install some glibc patches. However, I have glibc 2.13 running. Should I be concerned?
I found a c program on a site talking about the ghost issue and used it to test my system.
http://www.cyberciti.biz/faq/cve-2015-0235-patch-ghost-on-debian-ubuntu-fedora-centos-rhel-linux/mark@swordfish:~/ghost-test$ ldd --version
ldd (Debian EGLIBC 2.13-38+deb7u7) 2.13
I am running Debian GNU/Linux 7 (wheezy).