https://rhn.redhat.com/errata/RHSA-2004-569.html refers

Updated files are :-

mysql-3.23.58-2.3.i386.rpm mysql-bench-3.23.58-2.3.i386.rpm mysql-devel-3.23.58-2.3.i386.rpm mysql-server-3.23.58-2.3.i386.rpm

in updates/i386/RPMS/

These are available at http://mirror.centos.org/3.3/ and should be on all mirrors within a few hours.

To update to the latest version 'yum update mysql' should be sufficient.

Lance