Smoothwall Express Stored Cross-Site Scripting Vulnerability in VPN Configuration

A stored cross-site scripting vulnerability has been identified in Smoothwall Express versions prior to 3.1 Update 13. The issue resides in the /cgi-bin/vpnmain.cgi script, where improper sanitation of the VPN_IP parameter allows authenticated attackers to inject arbitrary JavaScript. This injected script executes when the affected page is viewed by other users.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the affected page.

Remediation

Users can update to Smoothwall Express 3.1 Update 13 or later, which addresses this vulnerability by improving input sanitation in the VPN management interface.