---
id: CVE-2026-109718
title: Use-after-free in the XML component
summary: >-
  Use-after-free in the XML component. This vulnerability was fixed in Firefox
  158, Firefox ESR 115.43, Firefox ESR 153.5, Thunderbird 158, and Thunderbird
  153.5.
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'
cwe:
  - CWE-416
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T19:18:35.440'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109718'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2073692'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-106/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-107/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-108/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-109/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-110/'
    label: security@mozilla.org
tags:
  - nvd
ingestedAt: '2026-10-13T13:27:03.995Z'
---

## Overview

Use-after-free in the XML component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

## Remediation

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