The following errata for CentOS-2 have been built and uploaded the the centos mirror:
RHSA-2004:421-01 Updated mozilla packages fix security issues
CentOS-2 c2.1 release also fixes redhat bug #120019
Files available: mozilla-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-chat-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-devel-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-dom-inspector-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-js-debugger-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-mail-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-nspr-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-nspr-devel-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-nss-1.4.3-2.1.2.c2.1.i386.rpm: mozilla-nss-devel-1.4.3-2.1.2.c2.1.i386.rpm: galeon-1.2.13-3.2.1.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