---
id: "CVE-2026-124903"
page: "https://infrastack.ai/live/CVE-2026-124903"
kind: "vulnerability"
aliases: ["CVE-2026-124903"]
title: "Firefox: use-after-free in IPC lets a sandbox escape happen"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Firefox", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["desktop-browsers", "firefox", "other"]
not_affected_if: ["fixed-version"]
published_at: "2026-11-10T14:17:23+00:00"
first_seen_at: "2026-11-10T14:22:17+00:00"
updated_at: "2026-11-10T14:24:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-124903", "first_seen_at": "2026-11-10T14:22:17+00:00"}]
exploit_sources: []
---

# Firefox: use-after-free in IPC lets a sandbox escape happen

Link for people: https://infrastack.ai/live/CVE-2026-124903 (this .md is for agents)

A use-after-free bug in Firefox's IPC component allows a sandbox escape. An attacker who can run content in the browser could get past the sandbox restrictions meant to contain it.

_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 with `about:support` or the Help menu; compare against the fixed versions below.
- Check ESR installs against `115.45` and `153.7`.

## Fix

- Firefox `160`
- Firefox ESR `115.45`
- Firefox ESR `153.7`

## Timeline

- 2026-11-10T14:22:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-124903

## From the sources

Sandbox escape due to use-after-free in the IPC component. This vulnerability was fixed in Firefox 160, Firefox ESR 115.45, and Firefox ESR 153.7.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_