It was discovered that patch applied to cups packages as shipped in Red Hat Enterprise Linux 3 and 4 to address security issues in xpdf code known as CVE-2004-0888 / CVE-2005-0206 was incomplete. On certain platforms, malicious pdf file could still cause a crash or possibly cause code execution when it's processed by pdftops filter. This issue affects 64-bit platforms. cups packages in Red Hat Enterprise Linux 5 are not affected by this problem.
This issue was addressed in: Red Hat Enterprise Linux: http://rhn.redhat.com/errata/RHSA-2008-0206.html