Detections
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Mozilla Firefox ESR < 115.42

critical Nessus Plugin ID 351121

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 115.42. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-98 advisory.

 - Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, Thunderbird 153.3, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-92035)

 - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

 - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

 - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100758)

 - Uninitialized memory in the Storage: Quota Manager component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100759)

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 115.42 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-98/

Plugin Details

Severity: Critical

ID: 351121

File Name: mozilla_firefox_115_42_esr.nasl

Version: 1.1

Type: Local

Agent: windows

Family: Windows

Published: 9/29/2026

Updated: 9/29/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.19

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-92035

CVSS v3

Risk Factor: Critical

Base Score: 9.6

Temporal Score: 8.3

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:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:mozilla:firefox_esr

Required KB Items: installed_sw/Mozilla Firefox ESR

Exploit Ease: No known exploits are available

Patch Publication Date: 9/29/2026

Vulnerability Publication Date: 9/15/2026

Reference Information

CVE: CVE-2026-100756, CVE-2026-100757, CVE-2026-100758, CVE-2026-100759, CVE-2026-100762, CVE-2026-100766, CVE-2026-100767, CVE-2026-100770, CVE-2026-100771, CVE-2026-100773, CVE-2026-100774, CVE-2026-100775, CVE-2026-100777, CVE-2026-100778, CVE-2026-100779, CVE-2026-100780, CVE-2026-100781, CVE-2026-100782, CVE-2026-100783, CVE-2026-100784, CVE-2026-100785, CVE-2026-100786, CVE-2026-100789, CVE-2026-100790, CVE-2026-100791, CVE-2026-100797, CVE-2026-100803, CVE-2026-100819, CVE-2026-100821, CVE-2026-100832, CVE-2026-92035