When using nested workers, a use-after-free could occur during worker destruction. This resulted in a potentially exploitable crash. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00000.html
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00001.html
https://bugzilla.mozilla.org/show_bug.cgi?id=1546331
https://usn.ubuntu.com/4241-1/
https://www.mozilla.org/security/advisories/mfsa2019-36/
Source: MITRE
Published: 2020-01-08
Updated: 2020-01-16
Type: CWE-416
Base Score: 6.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 8.8
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.8
Severity: HIGH