---
id: CVE-2026-92023
title: Use-after-free in the XML component
summary: >-
  Use-after-free in the XML component. This vulnerability was fixed in Firefox
  156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird
  156, Thunderbird 140.16, and Thunderbird 153.3.
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
  - CWE-825
vendor: Mozilla
product: Firefox
affected:
  - Firefox
  - Thunderbird
published: '2026-09-15'
updated: '2026-09-20'
sourceUpdated: '2026-09-20T01:16:35.217'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92023'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2068342'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-91/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-92/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-93/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-95/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-96/'
    label: security@mozilla.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92023.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-92023'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2533799'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-92023'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92023'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-92/#CVE-2026-92023'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-95/#CVE-2026-92023'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-20T00:17:34.152140Z'
epss: 0.0034
epssPercentile: 0.27519
scores:
  nvd: 8.8
  vendor: 7.5
  adp: 8.8
ingestedAt: '2026-09-15T12:36:50.193Z'
---

## Overview

Use-after-free in the XML component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, … · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92023.json)