Multiple cross-site scripting (XSS) vulnerabilities in Sophos Web Appliance before 3.7.8.2 allow remote attackers to inject arbitrary web script or HTML via the (1) xss parameter in an allow action to rss.php, (2) msg parameter to end-user/errdoc.php, (3) h parameter to end-user/ftp_redirect.php, or (4) threat parameter to the Blocked component.