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.
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.