A thunderbird security update has been released for CentOS 7.

CentOS Errata and Security Advisory 2020:0576 Important

Upstream details at :   https://access.redhat.com/errata/RHSA-2020:0576

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

x86_64:
7d68665877df01b039d49ab94dfd049eeb2f0eb35c3bc4f8d48f853eb0d56fa3 thunderbird-68.5.0-1.el7.centos.x86_64.rpm

Source:
b60f4ca1059f7dacd5e38fa71b5456168e78fc4955e9127f064b89c8b837cbea thunderbird-68.5.0-1.el7.centos.src.rpm