Mozilla Developer Iain Ireland discovered a missing type check during unboxed objects removal, resulting in a crash. We presume that with enough effort that it could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 68.9.0, Firefox < 77, and Firefox ESR < 68.9.
https://bugzilla.mozilla.org/show_bug.cgi?id=1639590
https://usn.ubuntu.com/4421-1/
https://www.mozilla.org/security/advisories/mfsa2020-20/
Source: MITRE
Published: 2020-07-09
Updated: 2020-07-22
Type: CWE-345
Base Score: 9.3
Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 8.6
Severity: HIGH
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