Multiple cross-site scripting (XSS) vulnerabilities in login.php in 3CX Phone System Free Edition 6.1793 and 6.0.806.0 allow remote attackers to inject arbitrary web script or HTML via the (1) fName and (2) fPassword parameters.

3CX Phone System 6.0.806.0 allows remote attackers to cause a denial of service (unstable service or crash) via unspecified vectors, as demonstrated by vulnerability scans from Nessus or SAINT.

login.php in 3CX Phone System 6.0.806.0, when 100% disk capacity is reached, allows remote attackers to gain sensitive information via unspecified vectors that reveal the installation path.

PhoneSystem Terminal in 3CX Phone System (Debian based installation) 16.0.0.1570 allows an authenticated attacker to run arbitrary commands with the phonesystem user privileges because of "<space><space> followed by <shift><enter>" mishandling.

PhoneSystem Terminal in 3CX Phone System (Debian based installation) 16.0.0.1570 allows an attacker to gain root privileges by using sudo with the tcpdump command, without a password. This occurs because the -z (aka postrotate-command) option to tcpdump can be unsafe when used in conjunction with sudo.