---
id: "CVE-2026-117943"
kind: "vulnerability"
aliases: ["CVE-2026-117943"]
title: "Firefox: use-after-free in DOM core lets page content corrupt memory"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["browser", "desktop", "firefox", "package"]
not_affected_if: ["no-firefox-installed", "patched-versions"]
published_at: "2026-10-27T14:16:49+00:00"
first_seen_at: "2026-10-27T14:32:23+00:00"
updated_at: "2026-10-27T14:35:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117943", "first_seen_at": "2026-10-27T14:32:23+00:00"}]
---

# Firefox: use-after-free in DOM core lets page content corrupt memory

A use-after-free flaw in the DOM Core and HTML component of Firefox was fixed in Firefox 159 and ESR 115.44 and 153.6. A use-after-free can let a crafted web page crash the browser or, in the worst case, run attacker code.

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

## How to check

- Run `firefox --version` (or check Help > About Firefox) and compare against `159` or the ESR builds `115.44` and `153.6`
- Check the ESR branch in use with `firefox --version` on managed machines

## Fix

- Update Firefox to `159` or later
- Update Firefox ESR to `115.44` or `153.6`, depending on the branch in use

## Timeline

- 2026-10-27T14:32:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117943

## From the sources

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.

---

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