---
id: "CVE-2026-124877"
page: "https://infrastack.ai/live/CVE-2026-124877"
kind: "vulnerability"
aliases: ["CVE-2026-124877"]
title: "Firefox: use-after-free in Layout Positioned component fixed in 160"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["browser", "firefox", "runtime"]
not_affected_if: ["already-on-fixed-version"]
published_at: "2026-11-10T14:17:20+00:00"
first_seen_at: "2026-11-10T14:22:14+00:00"
updated_at: "2026-11-10T14:26:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-124877", "first_seen_at": "2026-11-10T14:22:14+00:00"}]
exploit_sources: []
---

# Firefox: use-after-free in Layout Positioned component fixed in 160

Link for people: https://infrastack.ai/live/CVE-2026-124877 (this .md is for agents)

A use-after-free bug in Firefox's Layout: Positioned component lets memory be reused after it is freed. An attacker who gets a user to load a crafted page could potentially run code in the browser, though the sources do not state this.

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

## How to check

- Check the Firefox version in Help > About Firefox; affected builds are older than `160`, `115.45` (ESR) and `153.7` (ESR).

## Fix

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

## Timeline

- 2026-11-10T14:22:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-124877

## From the sources

Use-after-free in the Layout: Positioned 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_