pstotext before 1.9 allows user-assisted attackers to execute arbitrary commands via shell metacharacters in a file name.
http://www.vupen.com/english/advisories/2006/1707
http://www.securityfocus.com/bid/21299
http://www.securityfocus.com/bid/17897
http://www.debian.org/security/2006/dsa-1220
http://secunia.com/advisories/23135