---
id: "CVE-2026-117862"
kind: "vulnerability"
aliases: ["CVE-2026-117862"]
title: "Firefox: networking boundary bug lets an attacker escalate privileges"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["desktop", "firefox", "managed-fleet", "runtime"]
not_affected_if: ["already-on-fixed-version"]
published_at: "2026-10-27T14:16:40+00:00"
first_seen_at: "2026-10-27T14:32:21+00:00"
updated_at: "2026-10-27T14:39:23+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117862", "first_seen_at": "2026-10-27T14:32:21+00:00"}]
---

# Firefox: networking boundary bug lets an attacker escalate privileges

A boundary-condition error in Firefox's Networking component allows privilege escalation, according to the NVD description. The sources do not say what an attacker gains beyond the escalation or how it is triggered.

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

## How to check

- Run `firefox --version` (or check About Firefox) and compare against the fixed versions: Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6
- unknown for other checks: the sources do not say

## Fix

- Update Firefox to `159` or later
- Update Firefox ESR to `115.44` or `153.6`, whichever matches your ESR branch

## Timeline

- 2026-10-27T14:32:21+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117862

## From the sources

Privilege escalation due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_