A firefox security update has been released for CentOS 7.

CentOS-announce: CESA-2020:2037 Critical CentOS 7 firefox Security Update

CentOS Errata and Security Advisory 2020:2037 Critical

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:2037

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

x86_64:
db0fcf759d83908a5ffe7caeefa28f0c993645d279479cf421325f1d471af107 firefox-68.8.0-1.el7.centos.i686.rpm
d6f0f6f9010cdee8bb379c12e71356ef5661c56309bad50e2a58d113a15e2f13 firefox-68.8.0-1.el7.centos.x86_64.rpm

Source:
c0b1e18cb7b3f97715cc2af6e5d623853d24b7f2e763a779998cb9e3c6af3be0 firefox-68.8.0-1.el7.centos.src.rpm