---
id: "CVE-2026-117922"
kind: "vulnerability"
aliases: ["CVE-2026-117922"]
title: "Firefox: use-after-free in WebSockets networking 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: ["already-updated-firefox"]
published_at: "2026-10-27T14:16:47+00:00"
first_seen_at: "2026-10-27T14:32:22+00:00"
updated_at: "2026-10-27T14:37:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117922", "first_seen_at": "2026-10-27T14:32:22+00:00"}]
---

# Firefox: use-after-free in WebSockets networking lets attackers run code

A use-after-free bug in Firefox's WebSockets networking component can corrupt memory when a page or connection reuses freed memory. The sources do not say what an attacker can get beyond memory corruption.

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

## How to check

- Check the installed Firefox version in the About Firefox dialog or with `firefox --version`; affected builds are older than `159`, `115.44` ESR, and `153.6` ESR.
- Check whether the Firefox ESR branch in use is `115` or `153` and compare against the fixed `115.44` or `153.6`.

## 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

- 2026-10-27T14:32:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117922

## From the sources

Use-after-free in the Networking: WebSockets component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.

---

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