CVE 2010-1215

Mozilla Firefox 3.6.x before 3.6.7 and Thunderbird 3.1.x before 3.1.1 do not properly implement access to a content object through a SafeJSObjectWrapper (aka SJOW) wrapper, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges by leveraging "access to an object from the chrome scope."

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