New mozilla-firefox packages are available for Slackware 14.2 and -current to fix security issues.

Here are the details from the Slackware 14.2 ChangeLog:
+--------------------------+
patches/packages/mozilla-firefox-52.8.1esr-i586-1_slack14.2.txz: Upgraded.
This release contains security fixes and improvements.
For more information, see:
https://www.mozilla.org/security/known-vulnerabilities/firefoxESR.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 14.2:
ftp://ftp.slackware.com/pub/slackware/slackware-14.2/patches/packages/mozilla-firefox-52.8.1esr-i586-1_slack14.2.txz

Updated package for Slackware x86_64 14.2:
ftp://ftp.slackware.com/pub/slackware/slackware64-14.2/patches/packages/mozilla-firefox-52.8.1esr-x86_64-1_slack14.2.txz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/xap/mozilla-firefox-60.0.2-i686-1.txz

Updated package for Slackware x86_64 -current:
ftp://ftp.slackware.com/pub/slackware/slackware64-current/slackware64/xap/mozilla-firefox-60.0.2-x86_64-1.txz


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

Slackware 14.2 package:
8a96d3142dbdca05b04773faf34f2ea9 mozilla-firefox-52.8.1esr-i586-1_slack14.2.txz

Slackware x86_64 14.2 package:
685b47bc39d063ea734d60de7edb9107 mozilla-firefox-52.8.1esr-x86_64-1_slack14.2.txz

Slackware -current package:
ace4e29a69d2fe1c8c6f6ca8aa41b908 xap/mozilla-firefox-60.0.2-i686-1.txz

Slackware x86_64 -current package:
b444bdadcb0dac1c6d42768d9881f52f xap/mozilla-firefox-60.0.2-x86_64-1.txz


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

Upgrade the package as root:
# upgradepkg mozilla-firefox-52.8.1esr-i586-1_slack14.2.txz

  Mozilla-Firefox (SSA:2018-157-01) Update for Slackware