Mozilla Firefox ESR < 78.5

critical Nessus Plugin ID 142913

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Synopsis

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

Description

The version of Firefox ESR installed on the remote Windows host is prior to 78.5. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2020-51 advisory.

- Mozilla developers Steve Fink, Jason Kratzer, Randell Jesup, Christian Holler, and Byron Campen reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. (CVE-2020-26968)

- In Freetype, if PNG images were embedded into fonts, the <code>LoadSBitPng</code> function contained an integer overflow that led to a heap buffer overflow, memory corruption, and an exploitable crash. Note:
While Project Zero did discover instances of this vulnerability being exploited in the wild against Chrome, in Firefox this vulnerability is only triggerable if a rarely-used, hidden preference is toggled, and only affected Linux and Android operating systems. Other operating systems are unaffected; and Linux and Android are unaffected in the default configuration. (CVE-2020-15999)

- A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. (CVE-2020-26951)

- When drawing a transparent image on top of an unknown cross-origin image, the Skia library <code>drawImage</code> function took a variable amount of time depending on the content of the underlying image. This resulted in potential cross-origin information exposure of image content through timing side- channel attacks. (CVE-2020-16012)

- It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user. (CVE-2020-26953)

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

Solution

Upgrade to Mozilla Firefox ESR version 78.5 or later.

Plugin Details

Severity: Critical

ID: 142913

File Name: mozilla_firefox_78_5_esr.nasl

Version: 1.12

Type: local

Agent: windows

Family: Windows

Published: 11/17/2020

Updated: 11/18/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 10.0

CVSS v2

Risk Factor: High

Base Score: 9.3

Temporal Score: 8.1

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

CVSS Score Source: CVE-2020-26968

CVSS v3

Risk Factor: Critical

Base Score: 9.6

Temporal Score: 9.2

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

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

CVSS Score Source: CVE-2020-15999

Vulnerability Information

CPE: cpe:/a:mozilla:firefox_esr

Required KB Items: installed_sw/Mozilla Firefox ESR

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 11/17/2020

Vulnerability Publication Date: 10/20/2020

CISA Known Exploited Vulnerability Due Dates: 11/17/2021

Reference Information

CVE: CVE-2020-15999, CVE-2020-16012, CVE-2020-26951, CVE-2020-26953, CVE-2020-26956, CVE-2020-26958, CVE-2020-26959, CVE-2020-26960, CVE-2020-26961, CVE-2020-26965, CVE-2020-26966, CVE-2020-26968

IAVA: 2020-A-0537-S

MFSA: 2020-51

Detections

Analytics