A thunderbird security update has been released for Debian GNU/Linux 8 LTS

Package : thunderbird
Version : 1:68.3.0-2~deb8u1
CVE ID : CVE-2019-17005 CVE-2019-17008 CVE-2019-17010 CVE-2019-17011
CVE-2019-17012

Multiple security issues have been found in Thunderbird which could
potentially result in the execution of arbitrary code.

For Debian 8 "Jessie", these problems have been fixed in version
1:68.3.0-2~deb8u1.

We recommend that you upgrade your thunderbird packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS