The host is installed with Mozilla Firefox before 3.6.24 or 4.x through 7.0 or Thunderbird before 3.1.6 or 5.0 through 7.0 and is prone to cross-site scripting (XSS) vulnerability. A flaw is present in the applications, which fail to handle Shift-JIS encodings. Successful exploitation allows remote attackers to inject arbitrary web script or HTML.