PhpTax version 0.8 contains a remote code execution vulnerability in drawimage.php. The pfilez GET parameter is unsafely passed to the exec() function without sanitization. A remote attacker can inject arbitrary shell commands, leading to code execution under the web server's context. No authentication is required.
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.