Detections
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Mozilla Thunderbird < 153.2

critical Nessus Plugin ID 342260

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Synopsis

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

Description

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 153.2. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-88 advisory.

 - Privilege escalation due to invalid pointer in the Graphics component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2. (CVE-2026-84131)

 - Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2. (CVE-2026-75874)

 - Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used.
 (CVE-2026-84639)

 - A maliciously constructed mail header could lead to a one byte read past the end of a buffer.
 (CVE-2026-84640)

 - A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. (CVE-2026-84641)

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 153.2 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-88/

Plugin Details

Severity: Critical

ID: 342260

File Name: macos_thunderbird_153_2.nasl

Version: 1.4

Type: Local

Agent: macosx

Published: 9/1/2026

Updated: 9/11/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.56

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-2026-84143

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:thunderbird

Required KB Items: installed_sw/Mozilla Thunderbird

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 9/1/2026

Vulnerability Publication Date: 8/18/2026

Reference Information

CVE: CVE-2026-74952, CVE-2026-75874, CVE-2026-84118, CVE-2026-84119, CVE-2026-84120, CVE-2026-84121, CVE-2026-84122, CVE-2026-84123, CVE-2026-84124, CVE-2026-84125, CVE-2026-84129, CVE-2026-84130, CVE-2026-84131, CVE-2026-84132, CVE-2026-84133, CVE-2026-84134, CVE-2026-84136, CVE-2026-84137, CVE-2026-84139, CVE-2026-84140, CVE-2026-84141, CVE-2026-84143, CVE-2026-84144, CVE-2026-84145, CVE-2026-84637, CVE-2026-84639, CVE-2026-84640, CVE-2026-84641, CVE-2026-84642

IAVA: 2026-A-0877, 2026-A-0929