mod_auth_any package in Red Hat Enterprise Linux 2.1 and other operating systems does not properly escape arguments when calling other programs, which allows attackers to execute arbitrary commands via shell metacharacters.
https://exchange.xforce.ibmcloud.com/vulnerabilities/11893
http://www.securityfocus.com/bid/7448
http://www.redhat.com/support/errata/RHSA-2003-113.html
http://www.itlab.musc.edu/webNIS/mod_auth_any.html