Launchpad.net

CVE 2009-0771

The layout engine in Mozilla Firefox before 3.0.7, Thunderbird before 2.0.0.21, and SeaMonkey 1.1.15 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via certain vectors that trigger memory corruption and assertion failures.

See the CVE page on Mitre.org for more details.