CVE 2014-1512
Use-after-free vulnerability in the TypeObject class in the JavaScript engine in Mozilla Firefox before 28.0, Firefox ESR 24.x before 24.4, Thunderbird before 24.4, and SeaMonkey before 2.25 allows remote attackers to execute arbitrary code by triggering extensive memory consumption while garbage collection is occurring, as demonstrated by improper handling of BumpChunk objects.
See the 
CVE page on Mitre.org
for more details.
