A thunderbird security update has been released for CentOS 7.

CESA-2021:1192 Moderate CentOS 7 thunderbird Security Update

CentOS Errata and Security Advisory 2021:1192 Moderate

Upstream details at :   https://access.redhat.com/errata/RHSA-2021:1192

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

x86_64:
89b015eb0d04659b187b7cae8d68fd38cdfd6ebc31ef6a4cc9432e777fe5c452 thunderbird-78.9.1-1.el7.centos.x86_64.rpm

Source:
0a6c601af8bd999761c7d0669ac00e0b7246d487efefdfd634ea869fdd665891 thunderbird-78.9.1-1.el7.centos.src.rpm