Shutdown demonstrated that it was possible to use a JavaScript watch() to gain elevated privilege. This could be used to compromise the user's computer and install malware.
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.
Upgrade to the fixed versions. Do not enable JavaScript in Thunderbird or the mail portion of SeaMonkey.
Exploit details withheld during the active upgrade period.