---
id: "CVE-2026-117904"
kind: "vulnerability"
aliases: ["CVE-2026-117904"]
title: "Firefox: JavaScript garbage collector use-after-free fixed in 159"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["desktop-browsers", "firefox", "runtime"]
not_affected_if: ["esr-153.6-or-later", "firefox-159-or-later"]
published_at: "2026-10-27T14:16:45+00:00"
first_seen_at: "2026-10-27T14:32:22+00:00"
updated_at: "2026-10-27T14:37:35+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117904", "first_seen_at": "2026-10-27T14:32:22+00:00"}]
---

# Firefox: JavaScript garbage collector use-after-free fixed in 159

A use-after-free bug in the JavaScript garbage collector of Firefox can corrupt memory when the browser runs crafted script. The sources say it was fixed in Firefox 159 and Firefox ESR 153.6, but do not describe the attacker's exact outcome.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Firefox version in the browser's About page or with `firefox --version`, and compare it to `159` or `153.6` for ESR.

## Fix

- Update Firefox to `159` or later, or Firefox ESR to `153.6` or later.

## Timeline

- 2026-10-27T14:32:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117904

## From the sources

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

---

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