---
id: "CVE-2026-117916"
kind: "vulnerability"
aliases: ["CVE-2026-117916"]
title: "Firefox: use-after-free in XSLT component could let a page 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-browser"]
published_at: "2026-10-27T14:16:47+00:00"
first_seen_at: "2026-10-27T14:32:22+00:00"
updated_at: "2026-10-27T14:37:23+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117916", "first_seen_at": "2026-10-27T14:32:22+00:00"}]
---

# Firefox: use-after-free in XSLT component could let a page run code

A use-after-free bug in the XSLT component of Firefox was fixed in Firefox 159 and Firefox ESR 153.6. Use-after-free flaws can let a crafted page corrupt memory and may allow an attacker to run code in the browser.

_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`.
- unknown for any other check; the sources do not say.

## Fix

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

## Timeline

- 2026-10-27T14:32:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117916

## From the sources

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

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_