The following errata for CentOS-2 have been built and uploaded the the centos mirror:
RHSA-2004:378-01 Updated Ethereal packages fix security issues
Files available: ethereal-0.10.5-0.AS21.2.i386.rpm: ethereal-gnome-0.10.5-0.AS21.2.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