Mozilla Firefox ESR < 68.6.1

high Nessus Plugin ID 135201


A web browser installed on the remote Windows host is affected by multiple vulnerabilities.


The version of Firefox ESR installed on the remote Windows host is prior to 68.6.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2020-11 advisory.

- Under certain conditions, when running the nsDocShell destructor, a race condition can cause a use-after-free.
We are aware of targeted attacks in the wild abusing this flaw. (CVE-2020-6819)

- Under certain conditions, when handling a ReadableStream, a race condition can cause a use-after- free. We are aware of targeted attacks in the wild abusing this flaw. (CVE-2020-6820)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to Mozilla Firefox ESR version 68.6.1 or later.

See Also

Plugin Details

Severity: High

ID: 135201

File Name: mozilla_firefox_68_6_1_esr.nasl

Version: 1.8

Type: local

Agent: windows

Family: Windows

Published: 4/6/2020

Updated: 1/24/2022

Supported Sensors: Nessus Agent

Risk Information

CVSS Score Source: CVE-2020-6820


Risk Factor: Medium

Score: 6.7


Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.9

Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P

Temporal Vector: E:H/RL:OF/RC:C


Risk Factor: High

Base Score: 8.1

Temporal Score: 7.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:H/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:mozilla:firefox_esr

Required KB Items: Mozilla/Firefox/Version

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/3/2020

Vulnerability Publication Date: 4/3/2020

CISA Known Exploited Dates: 5/3/2022

Reference Information

CVE: CVE-2020-6819, CVE-2020-6820

MFSA: 2020-11

IAVA: 2020-A-0128-S