---
id: CVE-2026-113869
title: Use-after-free in S/MIME decryption during a security device password prompt
summary: >-
  When Thunderbird asked for a security device password (for example a smartcard
  PIN or the Primary Password) while decrypting an S/MIME message, the message
  load could finish or be cancelled while the prompt was open. This freed the
  messa…
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L'
cvssSource: adp
vendor: Mozilla
product: Thunderbird
affected:
  - Thunderbird
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-20T19:42:14.775611Z'
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T19:42:17.936Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-113869'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2075530'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-114/'
tags:
  - cve.org
ingestedAt: '2026-10-20T20:18:14.533Z'
---

## Overview

When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1.

## Affected

- `Thunderbird`

## Remediation

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