Using remote content in encrypted messages can lead to the disclosure of plaintext. This vulnerability affects Thunderbird ESR < 52.8 and Thunderbird < 52.8.
http://www.securityfocus.com/bid/104240
http://www.securitytracker.com/id/1040946
https://access.redhat.com/errata/RHSA-2018:1725
https://access.redhat.com/errata/RHSA-2018:1726
https://bugzilla.mozilla.org/show_bug.cgi?id=1411592
https://lists.debian.org/debian-lts-announce/2018/05/msg00013.html
https://security.gentoo.org/glsa/201811-13
https://usn.ubuntu.com/3660-1/
Source: MITRE
Published: 2018-06-11
Updated: 2019-03-13
Type: CWE-326
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH