mod_nss 1.0.8 and earlier, when NSSVerifyClient is set to none for the server/vhost context, does not enforce the NSSVerifyClient setting in the directory context, which allows remote attackers to bypass intended access restrictions.
https://bugzilla.redhat.com/show_bug.cgi?id=1016832
http://rhn.redhat.com/errata/RHSA-2013-1779.html
http://lists.opensuse.org/opensuse-updates/2013-12/msg00118.html