---
id: CVE-2026-92039
title: 'Mitigation bypass in the DOM: Notifications component'
summary: >-
  Mitigation bypass in the DOM: Notifications component. This vulnerability was
  fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird
  153.3.
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'
cwe:
  - CWE-693
  - CWE-358
vendor: Mozilla
product: Firefox
affected:
  - Firefox
  - Thunderbird
published: '2026-09-15'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T18:17:12.660'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92039'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2001265'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-93/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-96/'
    label: security@mozilla.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92039.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-92039'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2533735'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-92039'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92039'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/#CVE-2026-92039'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/#CVE-2026-92039'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00316
epssPercentile: 0.21859
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T17:26:42.531054Z'
scores:
  nvd: 6.3
  vendor: 6.1
  adp: 6.3
ingestedAt: '2026-09-15T12:36:50.187Z'
---

## Overview

Mitigation bypass in the DOM: Notifications component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92039.json)