cgi-bin/cgiServer.exx in Yealink VoIP Phone SIP-T38G allows remote authenticated users to execute arbitrary commands by calling the system method in the body of a request, as demonstrated by running unauthorized services, changing directory permissions, and modifying files.
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.