JIT optimizations involving the Javascript arguments object could confuse later optimizations. This risk was already mitigated by various precautions in the code, resulting in this bug rated at only moderate severity. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.
http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00025.html
https://bugzilla.mozilla.org/show_bug.cgi?id=1647293
https://usn.ubuntu.com/4443-1/
https://www.mozilla.org/security/advisories/mfsa2020-30/
Source: MITRE
Published: 2020-08-10
Updated: 2020-08-18
Type: CWE-843
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