Here are the details from the Slackware 14.0 ChangeLog:
+--------------------------+
patches/packages/mozilla-thunderbird-17.0.10esr-i486-1_slack14.0.txz: Upgraded.
This release contains security fixes and improvements.
For more information, see:
http://www.mozilla.org/security/known-vulnerabilities/thunderbirdESR.html
(* Security fix *)
+--------------------------+


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

Thanks to the friendly folks at the OSU Open Source Lab
(http://osuosl.org) for donating 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 13.37:
ftp://ftp.slackware.com/pub/slackware/slackware-13.37/patches/packages/mozilla-thunderbird-17.0.10esr-i486-1_slack13.37.txz

Updated package for Slackware x86_64 13.37:
ftp://ftp.slackware.com/pub/slackware/slackware64-13.37/patches/packages/mozilla-thunderbird-17.0.10esr-x86_64-1_slack13.37.txz

Updated package for Slackware 14.0:
ftp://ftp.slackware.com/pub/slackware/slackware-14.0/patches/packages/mozilla-thunderbird-17.0.10esr-i486-1_slack14.0.txz

Updated package for Slackware x86_64 14.0:
ftp://ftp.slackware.com/pub/slackware/slackware64-14.0/patches/packages/mozilla-thunderbird-17.0.10esr-x86_64-1_slack14.0.txz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/xap/mozilla-thunderbird-24.1.0-i486-1.txz

Updated package for Slackware x86_64 -current:
ftp://ftp.slackware.com/pub/slackware/slackware64-current/slackware64/xap/mozilla-thunderbird-24.1.0-x86_64-1.txz


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

Slackware 13.37 package:
991bfbd613a42ac8088118f824d77f15 mozilla-thunderbird-17.0.10esr-i486-1_slack13.37.txz

Slackware x86_64 13.37 package:
ded7c8bfdb23fe335f5be18b76874420 mozilla-thunderbird-17.0.10esr-x86_64-1_slack13.37.txz

Slackware 14.0 package:
f2195286f809a1e0df44fb2a08c9c9ba mozilla-thunderbird-17.0.10esr-i486-1_slack14.0.txz

Slackware x86_64 14.0 package:
2e67fdb730d5c585d6489adb65aadc72 mozilla-thunderbird-17.0.10esr-x86_64-1_slack14.0.txz

Slackware -current package:
5896f50d2a7b8e7b0cd98bbfafbe3884 xap/mozilla-thunderbird-24.1.0-i486-1.txz

Slackware x86_64 -current package:
385e35f8a0ebfbdb0e89bd13e8f4b120 xap/mozilla-thunderbird-24.1.0-x86_64-1.txz


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

Upgrade the package as root:
# upgradepkg mozilla-thunderbird-17.0.10esr-i486-1_slack14.0.txz


+-----+

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