---
id: CVE-2026-92034
title: Site isolation issue in the Graphics component
summary: >-
  Site isolation issue in the Graphics component. This vulnerability was fixed
  in Firefox 156 and Thunderbird 156.
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'
cwe:
  - CWE-346
  - CWE-653
vendor: mozilla
product: firefox
affected:
  - firefox < 156.0.0
  - thunderbird < 156.0
patched:
  - firefox 156.0.0
  - thunderbird 156.0
published: '2026-09-15'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T18:00:25.463'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92034'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2060295'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/'
    label: security@mozilla.org
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/'
    label: security@mozilla.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92034.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-92034'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2533759'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-92034'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92034'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/#CVE-2026-92034'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/#CVE-2026-92034'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00274
epssPercentile: 0.19728
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-21T17:04:54.752406Z'
scores:
  nvd: 9.1
  vendor: 7.5
ingestedAt: '2026-09-15T12:36:50.188Z'
---

## Overview

Site isolation issue in the Graphics component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.

## Affected

- `firefox < 156.0.0`
- `thunderbird < 156.0`

## Remediation

Upgrade past the affected range:

- `firefox 156.0.0`
- `thunderbird 156.0`

## Vendor advisories

- **Red Hat VEX** · Important · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92034.json)