Detections
Analytics

Mozilla Firefox ESR < 115.34.1

critical Nessus Plugin ID 305160

Synopsis

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

Description

The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 115.34.1. It is, therefore, affected by a vulnerability as referenced in the mfsa2026-26 advisory.

 - Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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-2026-5731)

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

Solution

Upgrade to Mozilla Firefox ESR version 115.34.1 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-26/

Plugin Details

Severity: Critical

ID: 305160

File Name: macos_firefox_115_34_1_esr.nasl

Version: 1.2

Type: Local

Agent: macosx

Published: 4/7/2026

Updated: 4/8/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2026-5731

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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: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: 4/7/2026

Vulnerability Publication Date: 4/7/2026

Reference Information

CVE: CVE-2026-5731