Vulnerability Instance

moz_bug_r_a4 discovered that the compilation scope of privileged
built-in XBL bindings was not fully protected from web content and
could be accessed by calling valueOf.call()
and valueOf.apply() on a method of that binding. This could then
be used to compile and run attacker-supplied JavaScript, giving it
the privileges of the binding which would allow an attacker
to install malware such as viruses and password sniffers.shutdown reported an alternate way to get to XBL compilation scope
by inserting an XBL method into the DOM's document.body
prototype chain.Thunderbird shares the JavaScript engine with Firefox
and could be vulnerable if JavaScript were to be enabled in mail. This is not
the default setting and we strongly discourage users from running
JavaScript in mail.