Detections
Analytics

Mozilla Firefox ESR < 140.14

critical Nessus Plugin ID 337630

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Synopsis

A web browser installed on the remote macOS or Mac OS X host is affected by multiple vulnerabilities.

Description

The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 140.14. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-76 advisory.

 - Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74944)

 - Site isolation issue in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74934)

 - Privilege escalation in the DOM: Networking component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74935)

 - Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
 (CVE-2026-74936)

 - Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74939)

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 140.14 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-76/

Plugin Details

Severity: Critical

ID: 337630

File Name: macos_firefox_140_14_esr.nasl

Version: 1.5

Type: Local

Agent: macosx

Published: 8/18/2026

Updated: 8/24/2026

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.19

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-2026-74944

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

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: 8/18/2026

Vulnerability Publication Date: 8/18/2026

Reference Information

CVE: CVE-2026-74934, CVE-2026-74935, CVE-2026-74936, CVE-2026-74939, CVE-2026-74940, CVE-2026-74941, CVE-2026-74942, CVE-2026-74943, CVE-2026-74944, CVE-2026-74945, CVE-2026-74946, CVE-2026-74948, CVE-2026-74949, CVE-2026-74953, CVE-2026-74957, CVE-2026-74959, CVE-2026-74960, CVE-2026-74962, CVE-2026-74963, CVE-2026-74964, CVE-2026-74965, CVE-2026-74967, CVE-2026-74969, CVE-2026-74971, CVE-2026-74972, CVE-2026-74973, CVE-2026-74974, CVE-2026-74976, CVE-2026-74983, CVE-2026-74987, CVE-2026-74990

IAVA: 2026-A-0876