CVE 2011-2985
Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox 4.x through 5, Thunderbird before 6, SeaMonkey 2.x before 2.3, and possibly other products allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.
See the 
CVE page on Mitre.org
for more details.
