Smoothwall Express 3.1-SP4-polar-x86_64-update9 contains multiple stored cross-site scripting vulnerabilities in the modem.cgi script that allow attackers to inject malicious scripts through POST parameters. Attackers can submit crafted payloads in parameters like INIT, HANGUP, SPEAKER_ON, SPEAKER_OFF, TONE_DIAL, and PULSE_DIAL to execute arbitrary JavaScript in users' browsers when the stored data is retrieved.