CentOS Errata and Security Advisory CESA-2005:434
https://rhn.redhat.com/errata/RHSA-2005-434.html
The following updated files have been uploaded and are currently syncing to the mirrors:
x86_64: firefox-1.0.4-1.4.1.centos4.x86_64.rpm
src: firefox-1.0.4-1.4.1.centos4.src.rpm