|Mozilla Firefox and Thunderbird before 18.104.22.168 allow remote attackers
to cause a denial of service (crash) and possibly execute arbitrary
code via (1) nested <option> tags in a select tag, (2) a
DOMNodeRemoved mutation event, (3) "Content-implemented tree views,"
(4) BoxObjects, (5) the XBL implementation, (6) an iframe that
attempts to remove itself, which leads to memory corruption.