---
id: "CVE-2026-117881"
kind: "vulnerability"
aliases: ["CVE-2026-117881"]
title: "Firefox: use-after-free in DOM core lets a page run code"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["browsers", "desktop", "firefox", "package"]
not_affected_if: ["already-on-fixed-version"]
published_at: "2026-10-27T14:16:43+00:00"
first_seen_at: "2026-10-27T14:32:21+00:00"
updated_at: "2026-10-27T14:37:58+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117881", "first_seen_at": "2026-10-27T14:32:21+00:00"}]
---

# Firefox: use-after-free in DOM core lets a page run code

A use-after-free bug in the DOM Core and HTML component of Firefox can be triggered by web content. Fixed in Firefox 159 and Firefox ESR 115.44 and 153.6; the sources do not state the exact impact beyond the memory corruption class.

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

## How to check

- Check the installed Firefox version in About Firefox or with `firefox --version`
- Compare against `159`, `115.44` (ESR) and `153.6` (ESR)
- unknown for anything beyond version checks

## Fix

- Update Firefox to `159` or later
- Update Firefox ESR to `115.44` or `153.6`
- unknown for any other mitigation

## Timeline

- 2026-10-27T14:32:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117881

## 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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