This issue did not affect the OpenSSH packages as distributed with Red Hat Enterprise Linux 2.1 or 3, as they do not support Trusted X11 forwarding.
For Red Hat Enterprise Linux 4 and 5, this issue was addressed via: https://rhn.redhat.com/errata/RHSA-2008-0855.html
Red Hat Security Errata
|Red Hat Enterprise Linux 5 (openssh)||RHSA-2008:0855||2008-08-22|
|Red Hat Enterprise Linux 4 (openssh)||RHSA-2008:0855||2008-08-22|
|Red Hat Enterprise Linux Extended Update Support 4.5 (openssh)||RHSA-2008:0855||2008-08-22|