CVE 2010-1780
Use-after-free vulnerability in WebKit in Apple Safari before 5.0.1 on Mac OS X 10.5 through 10.6 and Windows, and before 4.1.1 on Mac OS X 10.4; and webkitgtk before 1.2.6; allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via vectors related to element focus.
See the 
CVE page on Mitre.org
for more details.
