---
id: "CVE-2026-117887"
kind: "vulnerability"
aliases: ["CVE-2026-117887"]
title: "Firefox: use-after-free in DOM core and HTML lets attackers run code"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["browsers", "desktop", "firefox", "runtime"]
not_affected_if: []
published_at: "2026-10-27T14:16:44+00:00"
first_seen_at: "2026-10-27T14:32:21+00:00"
updated_at: "2026-10-27T14:37:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117887", "first_seen_at": "2026-10-27T14:32:21+00:00"}]
---

# Firefox: use-after-free in DOM core and HTML lets attackers run code

A use-after-free bug in the DOM Core and HTML component of Firefox was fixed in Firefox 159 and the ESR releases 115.44 and 153.6. Use-after-free flaws in browser engines are commonly abused to corrupt memory and may let a malicious web page execute code, but the sources do not say how it is triggered.

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

## How to check

- Run `firefox --version` (or check About Firefox) and compare against `159`, `115.44` and `153.6`.
- Check the ESR line in use: `115.44` or `153.6` for ESR installs.

## Fix

- Update Firefox to `159` or later.
- Update Firefox ESR 115 to `115.44` or later.
- Update Firefox ESR 153 to `153.6` or later.

## Timeline

- 2026-10-27T14:32:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117887

## 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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