---
id: "CVE-2026-117988"
kind: "vulnerability"
aliases: ["CVE-2026-117988"]
title: "Firefox: boundary error in WebGL canvas lets web content escape sandbox"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["browsers", "desktop", "firefox", "runtime", "webgl"]
not_affected_if: ["already-updated"]
published_at: "2026-10-27T14:16:56+00:00"
first_seen_at: "2026-10-27T14:32:24+00:00"
updated_at: "2026-10-27T14:35:03+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117988", "first_seen_at": "2026-10-27T14:32:24+00:00"}]
---

# Firefox: boundary error in WebGL canvas lets web content escape sandbox

A flaw in Firefox's Graphics CanvasWebGL component lets a crafted page break out of the browser's sandbox. Sources do not say what an attacker can reach after escaping.

_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 with `159` or `153.6` for ESR
- Confirm the installed version is below `159` (or below `153.6` on ESR)

## Fix

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

## Timeline

- 2026-10-27T14:32:24+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117988

## From the sources

Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.

---

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