CVE 2012-1967
Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 do not properly implement the JavaScript sandbox utility, which allows remote attackers to execute arbitrary JavaScript code with improper privileges via a javascript: URL.
See the 
CVE page on Mitre.org
for more details.
