DrayTek Vigor 3900 before v1.5.1.5_Beta, DrayTek Vigor 2960 before v1.5.1.5_Beta and DrayTek Vigor 300B before v1.5.1.5_Beta were discovered to contain a command injection vulnerability via the action parameter at cgi-bin/mainfunction.cgi.
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.