Security bugs are reported here via bugzilla

[Arwed von Merkatz <v.merkatz AT gmx.net>]

Two major security vulnerabilities have been found in thunderbird 1.0.7
and 1.5:
1)
Georgi Guninski reported two variants of using scripts in an XBL control
to gain chrome privileges when the page is viewed under "Print Preview".

This vulnerability exists even if web-content JavaScript is turned off.

http://www.mozilla.org/security/announce/2006/mfsa2006-25.html

2)
Georgi Guninski reports that forwarding mail in-line while using the
default HTML "rich mail" editor will execute JavaScript embedded in the
e-mail message. Forwarding mail in-line is not the default setting but
it is easily accessed through the "Forward As" menu item.

This JavaScript runs with the full privileges of the client and could be
used to install malware or send spam.

In Thunderbird 1.0.7 and below and Mozilla Suite 1.7.12 and below
JavaScript is also executed when you reply to a mail, though limited to
the sandbox of the message. This script could spy on or alter the
message you are composing.

http://www.mozilla.org/security/announce/2006/mfsa2006-21.html

This applies to all grimoires, every user of thunderbird should update:
# scribe update
# cast -c thunderbird

or

# scribe update
# sorcery queue-security
# cast --queue

-- 
Arwed v. Merkatz                              Source Mage GNU/Linux developer
                                                    http://www.sourcemage.org