CVE-2020-26950

high

Description

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.

References

https://www.mozilla.org/security/advisories/mfsa2020-49/

https://euvd.enisa.europa.eu/vulnerability/EUVD-2020-19474

https://bugzilla.mozilla.org/show_bug.cgi?id=1675905

http://packetstormsecurity.com/files/166175/Firefox-MCallGetProperty-Write-Side-Effects-Use-After-Free.html

Details

Source: Mitre, NVD

Published: 2020-12-09

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 9.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H