Not vulnerable. This issue did not affect the versions of CUPS as shipped with Red Hat Enterprise Linux 3, 4, or 5. Affected script is not part of the upstream CUPS distribution, but rather an addition used by Debian-based distributions (and possibly others). CUPS packages as shipped in Red Hat Enterprise Linux 5 also provide pstopdf filter. However, that filter is different from the one used in Debian-based distributions, and is unaffected by this flaw. Additionally, all filters used by CUPS on all versions of Red Hat Enterprise Linux are run under an unprivileged "lp" user, making the root privilege escalation mentioned in the published exploit impossible.