CVE 2012-5830
Use-after-free vulnerability in Mozilla Firefox before 17.0, Firefox ESR 10.x before 10.0.11, Thunderbird before 17.0, Thunderbird ESR 10.x before 10.0.11, and SeaMonkey before 2.14 on Mac OS X allows remote attackers to execute arbitrary code via an HTML document.
See the 
CVE page on Mitre.org
for more details.
