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

RHSA-2005:529-01 Important: kernel security update

Files available:
kernel-2.4.9-e.65.athlon.rpm
kernel-smp-2.4.9-e.65.athlon.rpm
kernel-BOOT-2.4.9-e.65.i386.rpm
kernel-doc-2.4.9-e.65.i386.rpm
kernel-headers-2.4.9-e.65.i386.rpm
kernel-source-2.4.9-e.65.i386.rpm
kernel-2.4.9-e.65.i686.rpm
kernel-debug-2.4.9-e.65.i686.rpm
kernel-enterprise-2.4.9-e.65.i686.rpm
kernel-smp-2.4.9-e.65.i686.rpm
kernel-summit-2.4.9-e.65.i686.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