To install updates do:
For debian/ubuntu based operating systems: apt-get update ; apt-get upgrade
For redhat/centos based operating systems: yum update
It would be a good idea to reboot your server after installing glibc updates.
For more information about this particular vulnerability you can read here - https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2015-7547
Wednesday, February 17, 2016