Description of problem: Thor Lancelot Simon discovered a flaw in the way sudo handles krb5 authentication that could be potentially exploited to gain elevated privileges by bypassing a local authentication.
Official Statement from Red Hat (6/11/2007) Not vulnerable. Versions of sudo package shipped with Red Hat Enterprise Linux versions 2.1, 3, 4 and 5 are linked with PAM support and never use libkrb5 authentication.