CVE-2020-26950

HIGH

Firefox MCallGetProperty Write Side Effects Use After Free Exploit

Title source: metasploit

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.

Exploits (1)

metasploit WORKING POC MANUAL

by 360 ESG Vulnerability Research Institute, maxpl0it, timwr · rubypoc

https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/browser/firefox_jit_use_after_free.rb

View Code ZIP pw:eip

References (3)

[Exploit, Issue Tracking, Vendor Advisory] https://bugzilla.mozilla.org/show_bug.cgi?id=1675905

[Vendor Advisory] https://www.mozilla.org/security/advisories/mfsa2020-49/

[Exploit, Third Party Advisory, VDB Entry] http://packetstormsecurity.com/files/166175/Firefox-MCallGetProperty-Write-Side-Effects-Use-After-Free.html

Scores

CVSS v3 8.8

EPSS 0.4827

EPSS Percentile 97.7%

Attack Vector NETWORK

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

Details

CWE

CWE-416

Status published

Products (3)

mozilla/firefox < 82.0.3

mozilla/firefox_esr < 78.4.1

mozilla/thunderbird < 78.4.2

Published Dec 09, 2020

Tracked Since Feb 18, 2026