CVE 2011-2373
Use-after-free vulnerability in Mozilla Firefox before 3.6.18 and 4.x through 4.0.1, Thunderbird before 3.1.11, and SeaMonkey through 2.0.14, when JavaScript is disabled, allows remote attackers to execute arbitrary code via a crafted XUL document.
See the
CVE page on Mitre.org
for more details.