first glibc is basically most of the operating system
if you change it you will need to rebuild about 99% of the operating system before it will start to run ever again
without knowing what
operating system this is -- we can not help
from the use of " rpm"
it is likely in the redhat family or suse family
for red hat based OS's you use yum
for the suse group of OS's you use zypper
and you use what IS IN THE update repo
for RHEL 5,6 ,and fedora
will install the latest that distro version
will install the latest for this distro version
but if you are intent on killing your operating system
to the point it will never run ever again
!!! do not do this !!!
rpm --force -i glibc-common-2.5-42.i386.rpm