Mozilla Thunderbird is a vulnerable to arbitrary code execution attacks. This is because of some of the memory safety bugs in Firefox which allows an attacker to execute arbitrary codes.
www.securityfocus.com/bid/101054
www.securitytracker.com/id/1039465
access.redhat.com/errata/RHSA-2017:2831
access.redhat.com/errata/RHSA-2017:2885
access.redhat.com/security/updates/classification/#important
bugzilla.mozilla.org/buglist.cgi?bug_id=1386787%2C1389974%2C1371657%2C1360334%2C1390550%2C1380824%2C1387918%2C1395598
lists.debian.org/debian-lts-announce/2017/11/msg00000.html
security.gentoo.org/glsa/201803-14
usn.ubuntu.com/3688-1/
www.debian.org/security/2017/dsa-3987
www.debian.org/security/2017/dsa-4014
www.mozilla.org/en-US/security/advisories/mfsa2017-23/
www.mozilla.org/security/advisories/mfsa2017-21/
www.mozilla.org/security/advisories/mfsa2017-22/
www.mozilla.org/security/advisories/mfsa2017-23/