An authenticated OS command injection vulnerability exists in various Linksys router models (tested on WRT160Nv2) running firmware version v2.0.03 via the apply.cgi endpoint. The web interface fails to properly sanitize user-supplied input passed to the ping_size parameter during diagnostic operations. An attacker with valid credentials can inject arbitrary shell commands, enabling remote code execution.
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.