New mozilla-thunderbird packages are available for Slackware 10.2, 11.0, 12.0, and -current to fix security issues.

Here are the details from the Slackware 12.0 ChangeLog:
+--------------------------+
patches/packages/mozilla-thunderbird-2.0.0.12-i686-1.tgz:
Upgraded to thunderbird-2.0.0.12.
This update fixes the following security related issues:
MFSA 2008-12: Heap buffer overflow in external MIME bodies
MFSA 2008-05: Directory traversal via chrome: URI
MFSA 2008-03: Privilege escalation, XSS, Remote Code Execution
MFSA 2008-01: Crashes with evidence of memory corruption (rv:1.8.1.12)
For more information, see:
http://www.mozilla.org/security/announce/2008/mfsa2008-12.html
http://www.mozilla.org/security/announce/2008/mfsa2008-05.html
http://www.mozilla.org/security/announce/2008/mfsa2008-03.html
http://www.mozilla.org/security/announce/2008/mfsa2008-01.html
These are the related CVE entries:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0304
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0418
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0415
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0412
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0413
(* Security fix *)
+--------------------------+


Where to find the new packages:
+-----------------------------+

HINT: Getting slow download speeds from ftp.slackware.com?
Give slackware.osuosl.org a try. This is another primary FTP site
for Slackware that can be considerably faster than downloading
directly from ftp.slackware.com.

Thanks to the friendly folks at the OSU Open Source Lab
(http://osuosl.org) for donating additional FTP and rsync hosting
to the Slackware project! :-)

Also see the "Get Slack" section on http://slackware.com for
additional mirror sites near you.

Updated package for Slackware 10.2:
ftp://ftp.slackware.com/pub/slackware/slackware-10.2/patches/packages/mozilla-thunderbird-2.0.0.12-i686-1.tgz

Updated package for Slackware 11.0:
ftp://ftp.slackware.com/pub/slackware/slackware-11.0/patches/packages/mozilla-thunderbird-2.0.0.12-i686-1.tgz

Updated package for Slackware 12.0:
ftp://ftp.slackware.com/pub/slackware/slackware-12.0/patches/packages/mozilla-thunderbird-2.0.0.12-i686-1.tgz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/xap/mozilla-thunderbird-2.0.0.12-i686-1.tgz


MD5 signatures:
+-------------+

Slackware 10.2 package:
0c5bfc8c508e128b13c88311a6889879 mozilla-thunderbird-2.0.0.12-i686-1.tgz

Slackware 11.0 package:
0c5bfc8c508e128b13c88311a6889879 mozilla-thunderbird-2.0.0.12-i686-1.tgz

Slackware 12.0 package:
0c5bfc8c508e128b13c88311a6889879 mozilla-thunderbird-2.0.0.12-i686-1.tgz

Slackware -current package:
0c5bfc8c508e128b13c88311a6889879 mozilla-thunderbird-2.0.0.12-i686-1.tgz


Installation instructions:
+------------------------+

Upgrade the package as root:
# upgradepkg mozilla-thunderbird-2.0.0.12-i686-1.tgz


+-----+

Slackware Linux Security Team
http://slackware.com/gpg-key