Smoothwall Express Cross-Site Scripting Vulnerability in Proxy CGI Endpoint

A cross-site scripting (XSS) vulnerability has been identified in Smoothwall Express version 3.1-SP4-polar-x86_64-update9. This vulnerability exists in the proxy.cgi endpoint, where attackers can inject malicious scripts through several parameters related to cache and size settings. The injected JavaScript is executed in the context of the user's browser when the proxy configuration page is accessed.

Impact

Exploitation of this vulnerability allows for cross-site scripting, where injected scripts are executed in the context of the user's browser.

Reproduction

The vulnerability can be reproduced by sending a POST request to the proxy.cgi endpoint with a script payload injected into one of the vulnerable parameters, such as CACHE_SIZE, MAX_SIZE, MIN_SIZE, MAX_OUTGOING_SIZE, or MAX_INCOMING_SIZE. The injected script will be executed when the proxy configuration page is accessed.