The following errata for CentOS-2 have been built and uploaded to the centos mirror:
RHSA-2005:823-01 Low: fetchmail security update
Files available: fetchmail-5.9.0-21.7.3.el2.1.2.i386.rpm fetchmailconf-5.9.0-21.7.3.el2.1.2.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