Mozilla developers and community members reported memory safety bugs present in Firefox 63 and Firefox ESR 60.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 60.4, Firefox ESR < 60.4, and Firefox < 64.
http://www.securityfocus.com/bid/106168
https://access.redhat.com/errata/RHSA-2018:3831
https://access.redhat.com/errata/RHSA-2018:3833
https://access.redhat.com/errata/RHSA-2019:0159
https://access.redhat.com/errata/RHSA-2019:0160
https://lists.debian.org/debian-lts-announce/2018/12/msg00002.html
https://security.gentoo.org/glsa/201903-04
https://usn.ubuntu.com/3844-1/
https://usn.ubuntu.com/3868-1/
https://www.debian.org/security/2018/dsa-4354
https://www.debian.org/security/2019/dsa-4362
https://www.mozilla.org/security/advisories/mfsa2018-29/
Source: MITRE
Published: 2019-02-28
Updated: 2019-03-12
Type: CWE-119
Base Score: 7.5
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 10
Severity: HIGH
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 3.9
Severity: CRITICAL