---
id: CVE-2026-92066
title: Sandbox escape in the Profile Backup component
summary: >-
  Sandbox escape in the Profile Backup component. This vulnerability was fixed
  in Firefox 156 and Thunderbird 156.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-693
  - CWE-653
vendor: Mozilla
product: Firefox
affected:
  - Firefox
  - Thunderbird
published: '2026-09-15'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T19:17:16.780'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92066'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2058093'
    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-2026-92066.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-92066'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2533768'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-92066'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92066'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-90/#CVE-2026-92066'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-94/#CVE-2026-92066'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00319
epssPercentile: 0.25052
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-21T18:09:43.796684Z'
scores:
  nvd: 9.8
  vendor: 3.4
  adp: 9.8
ingestedAt: '2026-09-15T12:36:50.178Z'
---

## Overview

Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Low · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92066.json)