A firefox Security Update has been released for CentOS 7

CentOS Errata and Security Advisory 2019:4107 Critical

Upstream details at :   https://access.redhat.com/errata/RHSA-2019:4107

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

x86_64:
3678d51d94d9f7e7dc1947751f008476929e70e336ee4bac73e1d13ccef85fc3 firefox-68.3.0-1.el7.centos.i686.rpm
dc7ea366fa674894be6c44c94899467a455067067e9f163e42e39c51306568b3 firefox-68.3.0-1.el7.centos.x86_64.rpm

Source:
3f813d565e388114a28950f86b316cd8afe4e3904190418f9e126c2235a512e5 firefox-68.3.0-1.el7.centos.src.rpm