The following errata for CentOS-2 have been built and uploaded the the centos mirror:

RHSA-2004:402-01 Updated libpng packages fix security issues

Files available: libpng-1.0.14-7.i386.rpm: libpng-devel-1.0.14-7.i386.rpm:

More details are available from the RedHat web site at https://rhn.redhat.com/errata/rh21as-errata.html

The easy way to make sure you are up to date with all the latest patches is to run: # yum update