---
id: CVE-2026-109774
title: 'Invalid pointer, undefined behavior in the DOM: Notifications component'
summary: >-
  Invalid pointer, undefined behavior in the DOM: Notifications component. This
  vulnerability was fixed in Firefox 158 and Thunderbird 158.
severity: critical
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T19:18:41.790'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109774'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2067657'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-106/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-109/'
    label: security@mozilla.org
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-13T13:27:04.016Z'
vendor: Mozilla
product: Firefox
affected:
  - Firefox
  - Thunderbird
epss: 0.00342
epssPercentile: 0.27544
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-26T19:20:16.654423Z'
cvssSource: adp
---

## Overview

Invalid pointer, undefined behavior in the DOM: Notifications component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

## Remediation

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