---
id: "CVE-2026-124900"
page: "https://infrastack.ai/live/CVE-2026-124900"
kind: "vulnerability"
aliases: ["CVE-2026-124900"]
title: "Firefox: use-after-free in Service Workers lets a web page escape its sandbox"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "Firefox", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["browser", "firefox", "package"]
not_affected_if: []
published_at: "2026-11-10T14:17:23+00:00"
first_seen_at: "2026-11-10T14:22:16+00:00"
updated_at: "2026-11-10T14:24:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-124900", "first_seen_at": "2026-11-10T14:22:16+00:00"}]
exploit_sources: []
---

# Firefox: use-after-free in Service Workers lets a web page escape its sandbox

Link for people: https://infrastack.ai/live/CVE-2026-124900 (this .md is for agents)

A use-after-free bug in the DOM Service Workers component of Firefox allows a sandbox escape. The sources say it was fixed in Firefox 160 but give no details on what an attacker can run once the sandbox is escaped.

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

## Affected

- vendor:Firefox affected range not listed fixed no fixed version listed

## How to check

- Check the installed Firefox version, for example in the About Firefox dialog, and compare it with `160`.

## Fix

- Firefox: `160`

## Timeline

- 2026-11-10T14:22:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-124900

## From the sources

Sandbox escape due to use-after-free in the DOM: Service Workers component. This vulnerability was fixed in Firefox 160.

---

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