Mozilla Firefox is vulnerable to use-after-free vulnerability. This is possible when using an incorrect URL during the reloading of a docshell which results in an application crash.
www.securityfocus.com/bid/99057
www.securitytracker.com/id/1038689
access.redhat.com/errata/RHSA-2017:1440
access.redhat.com/errata/RHSA-2017:1561
access.redhat.com/security/updates/classification/#critical
bugzilla.mozilla.org/show_bug.cgi?id=1355039
www.debian.org/security/2017/dsa-3881
www.debian.org/security/2017/dsa-3918
www.mozilla.org/en-US/security/advisories/mfsa2017-16/
www.mozilla.org/security/advisories/mfsa2017-15/
www.mozilla.org/security/advisories/mfsa2017-16/
www.mozilla.org/security/advisories/mfsa2017-17/