---
id: CVE-2026-118174
title: >-
  Displaying a message could load an attacker-chosen URL through an OpenPGP key
  attachment
summary: >-
  When a message containing an OpenPGP key attachment was displayed, Thunderbird
  automatically loaded the attachment's content to offer importing the key. A
  sender could mark the attachment as an external attachment pointing to an
  arbitrar…
severity: none
vendor: Mozilla
product: Thunderbird
affected:
  - Thunderbird
published: '2026-10-27'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T18:27:46.521Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118174'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2080910'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-121/'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-122/'
tags:
  - cve.org
ingestedAt: '2026-10-27T18:52:10.023Z'
---

## Overview

When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials.
The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

## Affected

- `Thunderbird`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.