Multiple cross-site scripting (XSS) vulnerabilities in Mozilla Firefox 4.x through 11.0, Firefox ESR 10.x before 10.0.4, Thunderbird 5.0 through 11.0, Thunderbird ESR 10.x before 10.0.4, and SeaMonkey before 2.9 allow remote attackers to inject arbitrary web script or HTML via the (1) ISO-2022-KR or (2) ISO-2022-CN character set.