Detections
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Mozilla Thunderbird < 140.9

critical Nessus Plugin ID 303503

Synopsis

A mail client installed on the remote Windows host is affected by multiple vulnerabilities.

Description

The version of Thunderbird installed on the remote Windows host is prior to 140.9. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-24 advisory.

 - Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. (CVE-2026-4717)

 - 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)

 - Spoofing issue in Thunderbird. This vulnerability affects Thunderbird < 149 and Thunderbird < 140.9.
 (CVE-2026-3889)

 - A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data.
 (CVE-2026-4371)

 - 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)

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 Thunderbird version 140.9 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-24/

Plugin Details

Severity: Critical

ID: 303503

File Name: mozilla_thunderbird_140_9.nasl

Version: 1.1

Type: local

Agent: windows

Family: Windows

Published: 3/24/2026

Updated: 3/24/2026

Supported Sensors: 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-2026-4717

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

CVSS Score Source: CVE-2026-4688

Vulnerability Information

CPE: cpe:/a:mozilla:thunderbird

Required KB Items: installed_sw/Mozilla Thunderbird

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-2026-3889, CVE-2026-4371, 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