CVE 2011-3659
Use-after-free vulnerability in Mozilla Firefox before 3.6.26 and 4.x through 9.0, Thunderbird before 3.1.18 and 5.0 through 9.0, and SeaMonkey before 2.7 might allow remote attackers to execute arbitrary code via vectors related to incorrect AttributeChildR
See the 
CVE page on Mitre.org
for more details.
