OPNsense Stored Cross-Site Scripting Vulnerability in System Advanced Sysctl Endpoint

A stored cross-site scripting vulnerability has been identified in OPNsense version 19.1, specifically within the system_advanced_sysctl.php endpoint. This vulnerability allows attackers to inject persistent malicious scripts via the tunable parameter. The injected scripts are stored and executed in the context of authenticated user sessions when the page is accessed.

Impact

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

Reproduction

To reproduce this vulnerability, send a POST request to the system_advanced_sysctl.php endpoint with a script payload in the tunable parameter. Once the payload is submitted, it will be executed when the page is viewed by an authenticated user.

Remediation

Users are advised to update to OPNsense version 19.1.1, which addresses this vulnerability.