TimThumb 2.8.13 and WordThumb 1.07, when Webshot (aka Webshots) is enabled, allows remote attackers to execute arbitrary commands via shell metacharacters in the src parameter.
https://code.google.com/p/timthumb/source/detail?r=219
https://code.google.com/p/timthumb/issues/detail?id=485
http://secunia.com/advisories/59558
http://seclists.org/oss-sec/2014/q2/689
http://seclists.org/fulldisclosure/2014/Jun/117
http://seclists.org/fulldisclosure/2014/Jul/4
http://packetstormsecurity.com/files/127192/TimThumb-2.8.13-Remote-Code-Execution.html