---
id: "CVE-2026-124872"
page: "https://infrastack.ai/live/CVE-2026-124872"
kind: "vulnerability"
aliases: ["CVE-2026-124872"]
title: "Firefox: use-after-free bug in the Cycle Collector component"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["browser", "firefox", "other"]
not_affected_if: ["already-on-fixed-version"]
published_at: "2026-11-10T14:17:19+00:00"
first_seen_at: "2026-11-10T14:22:14+00:00"
updated_at: "2026-11-10T14:26:26+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-124872", "first_seen_at": "2026-11-10T14:22:14+00:00"}]
exploit_sources: []
---

# Firefox: use-after-free bug in the Cycle Collector component

Link for people: https://infrastack.ai/live/CVE-2026-124872 (this .md is for agents)

Firefox has a use-after-free bug in its Cycle Collector component, which handles memory cleanup for objects. The sources do not state what an attacker can do with it.

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

## How to check

- Check the Firefox version with `about:support` or Help > About Firefox, and compare it with the fixed versions below.
- Check whether an ESR install is on `115.x` or `153.x`, since each branch has its own fixed version.

## 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-2026-124872

## From the sources

Use-after-free in the Cycle Collector 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_