CVE 2012-0471
Cross-site scripting (XSS) vulnerability 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 allows remote attackers to inject arbitrary web script or HTML via a multibyte character set.
See the 
CVE page on Mitre.org
for more details.
