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

RHSA-2006:0725-01 Moderate: qt security update

Files available:
qt-2.3.1-12.EL2.i386.rpm
qt-designer-2.3.1-12.EL2.i386.rpm
qt-devel-2.3.1-12.EL2.i386.rpm
qt-static-2.3.1-12.EL2.i386.rpm
qt-Xt-2.3.1-12.EL2.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