Detections
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Mozilla Firefox < 149.0

critical Nessus Plugin ID 303474

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Synopsis

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

Description

The version of Firefox installed on the remote Windows host is prior to 149.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-20 advisory.

 - Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability affects Firefox < 149 and Thunderbird < 149. (CVE-2026-4725)

 - Race condition, use-after-free in the Graphics: WebRender component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
 (CVE-2026-4684)

 - Incorrect boundary conditions in the Graphics: Canvas2D component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
 (CVE-2026-4685, CVE-2026-4686, CVE-2026-4706, CVE-2026-4707)

 - Sandbox escape due to incorrect boundary conditions in the Telemetry component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
 (CVE-2026-4687)

 - Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. (CVE-2026-4688)

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 version 149.0 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-20/

Plugin Details

Severity: Critical

ID: 303474

File Name: mozilla_firefox_149_0.nasl

Version: 1.4

Type: Local

Agent: windows

Family: Windows

Published: 3/24/2026

Updated: 3/27/2026

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

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-4725

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 9

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

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

Vulnerability Information

CPE: cpe:/a:mozilla:firefox

Required KB Items: installed_sw/Mozilla Firefox

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/24/2026

Vulnerability Publication Date: 6/10/2025

Reference Information

CVE: CVE-2025-59375, CVE-2026-4684, CVE-2026-4685, CVE-2026-4686, CVE-2026-4687, CVE-2026-4688, CVE-2026-4689, CVE-2026-4690, CVE-2026-4691, CVE-2026-4692, CVE-2026-4693, CVE-2026-4694, CVE-2026-4695, CVE-2026-4696, CVE-2026-4697, CVE-2026-4698, CVE-2026-4699, CVE-2026-4700, CVE-2026-4701, CVE-2026-4702, CVE-2026-4704, CVE-2026-4705, CVE-2026-4706, CVE-2026-4707, CVE-2026-4708, CVE-2026-4709, CVE-2026-4710, CVE-2026-4711, CVE-2026-4712, CVE-2026-4713, CVE-2026-4714, CVE-2026-4715, CVE-2026-4716, CVE-2026-4717, CVE-2026-4718, CVE-2026-4719, CVE-2026-4720, CVE-2026-4721, CVE-2026-4722, CVE-2026-4723, CVE-2026-4724, CVE-2026-4725, CVE-2026-4726, CVE-2026-4727, CVE-2026-4728, CVE-2026-4729

IAVA: 2026-A-0274