Sup before 0.13.2.1 and 0.14.x before 0.14.1.1 allows remote attackers to execute arbitrary commands via shell metacharacters in the filename of an email attachment.
http://www.openwall.com/lists/oss-security/2013/10/30/2
http://www.debian.org/security/2012/dsa-2805
http://secunia.com/advisories/55400
http://secunia.com/advisories/55294
http://rubyforge.org/pipermail/sup-talk/2013-October/004996.html
http://rubyforge.org/pipermail/sup-talk/2013-August/004993.html