OPNsense 19.1 Stored XSS via firewall_rules_edit.php

OPNsense 19.1 contains a stored cross-site scripting vulnerability that allows authenticated attackers to inject malicious scripts by submitting crafted input to the category parameter. Attackers can send POST requests to firewall_rules_edit.php with script payloads in the category field to execute arbitrary JavaScript in the browsers of other users accessing firewall rule pages.