---
id: CVE-2026-117994
title: 'Use-after-free in the JavaScript: GC component'
summary: >-
  Use-after-free in the JavaScript: GC component. This vulnerability was fixed
  in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
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'
cvssSource: adp
vendor: Mozilla
product: Firefox
affected:
  - Firefox
  - Thunderbird
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-05T16:43:32.610530Z'
published: '2026-10-27'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T16:43:46.159Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-117994'
references:
  - url: 'https://bugzilla.mozilla.org/show_bug.cgi?id=2080787'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-118/'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-120/'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-121/'
  - url: 'https://www.mozilla.org/security/advisories/mfsa2026-122/'
tags:
  - cve.org
epss: 0.00181
epssPercentile: 0.07788
ingestedAt: '2026-10-27T16:11:59.421Z'
---

## Overview

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

## Affected

- `Firefox`
- `Thunderbird`

## Remediation

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