CVE 2008-5511
Mozilla Firefox 3.x before 3.0.5 and 2.x before 2.0.0.19, Thunderbird 2.x before 2.0.0.19, and SeaMonkey 1.x before 1.1.14 allows remote attackers to bypass the same origin policy and conduct cross-site scripting (XSS) attacks via an XBL binding to an "unloaded document."
See the 
CVE page on Mitre.org
for more details.
