canto_curses/guibase.py in Canto Curses before 0.9.0 allows remote feed servers to execute arbitrary commands via shell metacharacters in a URL in a feed.
Improper Neutralization of Special Elements used in a Command The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.