A race condition exists in Firefox's handling of DOM element (tags) properties. Malicious HTML content could use this flaw to execute arbitrary code as the user running Firefox. This flaw does not affect the versions of SeaMonkey or Thunderbird shipped in Red Hat Enterprise Linux 3, 4, or 5.
This is now live: http://www.mozilla.org/security/announce/2010/mfsa2010-73.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2010:0809 https://rhn.redhat.com/errata/RHSA-2010-0809.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Via RHSA-2010:0808 https://rhn.redhat.com/errata/RHSA-2010-0808.html
This issue has been addressed in following products: Red Hat Enterprise Linux 3 Red Hat Enterprise Linux 4 Via RHSA-2010:0810 https://rhn.redhat.com/errata/RHSA-2010-0810.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Red Hat Enterprise Linux 5 Via RHSA-2010:0812 https://rhn.redhat.com/errata/RHSA-2010-0812.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2010:0861 https://rhn.redhat.com/errata/RHSA-2010-0861.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2010:0896 https://rhn.redhat.com/errata/RHSA-2010-0896.html