CentOS Errata and Security Advisory 2006:0543
https://rhn.redhat.com/errata/RHSA-2006-0543.html
The following updated files have been uploaded and are currently syncing to the mirrors:
i386: spamassassin-3.0.6-1.el4.x86_64.rpm
src: spamassassin-3.0.6-1.el4.src.rpm