Medium · published February 16, 2026
Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains multiple reflected cross-site scripting vulnerabilities in the apcupsd.cgi script that allow attackers to inject malicious scripts through multiple POST parameters. Attackers can submit crafted POST requests with script payloads in parameters like BATTLEVEL, RTMIN, BATTDELAY, TO, ANNOY, UPSIP, UPSNAME, UPSPORT, POLLTIME, UPSUSER, NISPORT, UPSAUTH, EMAIL, FROM, CC, SMSEMAIL, SMTPSERVER, PORT, USER, and EMAIL_PASSWORD to execute arbitrary JavaScript in victim browsers.