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-68.2.0esr-i686-1_slack14.2.txz: Upgraded.
This release contains security fixes and improvements.
For more information, see:
https://www.mozilla.org/en-US/firefox/68.2.0/releasenotes/
https://www.mozilla.org/security/known-vulnerabilities/firefoxESR.html
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-15903
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11757
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11758
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11759
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11760
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11761
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11762
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11763
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11764
(* 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-68.2.0esr-i686-1_slack14.2.txz

Updated package for Slackware x86_64 14.2:
ftp://ftp.slackware.com/pub/slackware/slackware64-14.2/patches/packages/mozilla-firefox-68.2.0esr-x86_64-1_slack14.2.txz

Updated package for Slackware -current:
ftp://ftp.slackware.com/pub/slackware/slackware-current/slackware/xap/mozilla-firefox-68.2.0esr-i686-1.txz

Updated package for Slackware x86_64 -current:
ftp://ftp.slackware.com/pub/slackware/slackware64-current/slackware64/xap/mozilla-firefox-68.2.0esr-x86_64-1.txz


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

Slackware 14.2 package:
439c3fddbbe04d5ea525598cbb07ca46 mozilla-firefox-68.2.0esr-i686-1_slack14.2.txz

Slackware x86_64 14.2 package:
414f4fa6867cef39168416347e5cbf30 mozilla-firefox-68.2.0esr-x86_64-1_slack14.2.txz

Slackware -current package:
1eb1505393581c5d65be10a4abb4eb99 xap/mozilla-firefox-68.2.0esr-i686-1.txz

Slackware x86_64 -current package:
c8fc2ebc5953de938738883b0efa14de xap/mozilla-firefox-68.2.0esr-x86_64-1.txz


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

Upgrade the package as root:
# upgradepkg mozilla-firefox-68.2.0esr-i686-1_slack14.2.txz

  Mozilla-Firefox (SSA:2019-295-01) Security Update for Slackware