CentOS Errata and Security Advisory 2006:0393
https://rhn.redhat.com/errata/RHSA-2006-0393.html
The following updated files have been uploaded and are currently syncing to the mirrors:
x86_64: ntp-4.2.0.a.20040617-4.EL4.1.x86_64.rpm
src: ntp-4.2.0.a.20040617-4.EL4.1.src.rpm