Here are the details from the Slackware 14.0 ChangeLog:
+--------------------------+
patches/packages/mozilla-firefox-16.0-i486-1_slack14.0.txz: Upgraded.
This release contains security fixes and improvements.
For more information, see:
http://www.mozilla.org/security/known-vulnerabilities/firefox.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-firefox-16.0-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-firefox-16.0-x86_64-1_slack13.37.txz

Updated package for Slackware 14.0:
ftp://ftp.slackware.com/pub/slackware/slackware-14.0/patches/packages/mozilla-firefox-16.0-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-firefox-16.0-x86_64-1_slack14.0.txz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/xap/mozilla-firefox-16.0-i486-1.txz

Updated package for Slackware x86_64 -current:
ftp://ftp.slackware.com/pub/slackware/slackware64-current/slackware64/xap/mozilla-firefox-16.0-x86_64-1.txz


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

Slackware 13.37 package:
29bb11fb476a0deba095a52fa404d21a mozilla-firefox-16.0-i486-1_slack13.37.txz

Slackware x86_64 13.37 package:
4e519807dfc0f3e1624a5580ea9991d4 mozilla-firefox-16.0-x86_64-1_slack13.37.txz

Slackware 14.0 package:
93783de27aad6a10d7bd4432df90eee2 mozilla-firefox-16.0-i486-1_slack14.0.txz

Slackware x86_64 14.0 package:
dd98523d46b575f31f600fd81657caf8 mozilla-firefox-16.0-x86_64-1_slack14.0.txz

Slackware -current package:
810e5194f8f22883670c72b35ae2a23e xap/mozilla-firefox-16.0-i486-1.txz

Slackware x86_64 -current package:
13d830a035d24d53dd14196fc3380250 xap/mozilla-firefox-16.0-x86_64-1.txz


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

Upgrade the package as root:
# upgradepkg mozilla-firefox-16.0-i486-1_slack14.0.txz


+-----+

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