---
id: "CVE-2026-117860"
kind: "vulnerability"
aliases: ["CVE-2026-117860"]
title: "Firefox: Navigation component lets pages bypass same-origin policy"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["browsers", "desktop", "firefox", "other"]
not_affected_if: ["firefox-159-or-later", "firefox-esr-153.6-or-later"]
published_at: "2026-10-27T14:16:40+00:00"
first_seen_at: "2026-10-27T14:32:21+00:00"
updated_at: "2026-10-27T14:39:25+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117860", "first_seen_at": "2026-10-27T14:32:21+00:00"}]
---

# Firefox: Navigation component lets pages bypass same-origin policy

A flaw in the DOM Navigation component of Firefox lets a page break the same-origin policy, which keeps one site from reading content of another. The sources do not say what data an attacker can reach or how the bypass is triggered.

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

## How to check

- Run `about:support` in Firefox and check the Application Basics version against `159` or `153.6` for ESR.
- unknown

## Fix

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

## Timeline

- 2026-10-27T14:32:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117860

## Documents

- [discussion] @TheHackersNews: Mozilla released Firefox 159 and security advisories for ESR 153.6 and 115.44.

 https://x.com/TheHackersNews/status/2115099732444119324

## From the sources

Same-origin policy bypass in the DOM: Navigation 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_