Detections
Analytics

Mozilla Thunderbird < 140.7.1

medium Nessus Plugin ID 297034

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Synopsis

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

Description

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 140.7.1. It is, therefore, affected by a vulnerability as referenced in the mfsa2026-08 advisory.

 - When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations, then it was possible to extract the secret contents of the email. (CVE-2026-0818)

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 Thunderbird version 140.7.1 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-08/

Plugin Details

Severity: Medium

ID: 297034

File Name: macos_thunderbird_140_7_1.nasl

Version: 1.3

Type: local

Agent: macosx

Published: 1/28/2026

Updated: 1/31/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 2.9

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2026-0818

CVSS v3

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.8

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

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

Vulnerability Information

CPE: cpe:/a:mozilla:thunderbird

Required KB Items: installed_sw/Mozilla Thunderbird

Exploit Ease: No known exploits are available

Patch Publication Date: 1/27/2026

Vulnerability Publication Date: 1/27/2026

Reference Information

CVE: CVE-2026-0818

IAVA: 2026-A-0091