Vulnerability Instance

Marius Schilder of Google Security reported that
when a XMLHttpRequest is made to a same-origin resource
which 302 redirects to a resource in a different domain, the response
from the cross-domain resource is readable by the site issuing the
XHR.  Cookies marked HttpOnly were not readable, but
other potentially sensitive data could be revealed in the XHR response
including URL parameters and content in the response body.Thunderbird shares the browser 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.