preview_email.cgi in Barracuda Spam Firewall (BSF) 3.3.01.001 through 3.3.03.053 allows remote attackers to execute commands via shell metacharacters ("|" pipe symbol) in the file parameter. NOTE: the attack can be extended to arbitrary commands by the presence of CVE-2006-4000.
https://exchange.xforce.ibmcloud.com/vulnerabilities/28234
http://www.securityfocus.com/bid/19276
http://www.securityfocus.com/archive/1/442249/100/0/threaded
http://www.securityfocus.com/archive/1/442132/100/0/threaded
http://securityreason.com/securityalert/1363
http://secunia.com/advisories/21258
http://archives.neohapsis.com/archives/fulldisclosure/2006-08/0110.html