---
id: "CVE-2026-121250"
kind: "vulnerability"
aliases: ["CVE-2026-121250"]
title: "Chrome: extension use-after-free lets a crafted extension escape the sandbox"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["browsers", "chrome", "desktop", "runtime"]
not_affected_if: ["chrome-up-to-date", "no-untrusted-extensions"]
published_at: "2026-11-03T21:17:35+00:00"
first_seen_at: "2026-11-03T21:19:29+00:00"
updated_at: "2026-11-03T21:21:00+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121250", "first_seen_at": "2026-11-03T21:19:29+00:00"}]
---

# Chrome: extension use-after-free lets a crafted extension escape the sandbox

A use-after-free bug in Chrome's Extensions component can be triggered by a crafted Chrome extension that a victim is tricked into installing. A successful attacker could potentially run code outside Chrome's sandbox.

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

## How to check

- Check the Chrome version with `chrome://settings/help` and compare it to `157.0.8103.38`
- Review installed extensions at `chrome://extensions` for anything unfamiliar

## Fix

- Google Chrome: move to `157.0.8103.38` or later

## Timeline

- 2026-11-03T21:19:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121250

## From the sources

Use after free in Extensions in Google Chrome prior to 157.0.8103.38 allowed a remote attacker leveraging social engineering to potentially execute arbitrary code outside the sandbox via a crafted Chrome extension. (Chromium security severity: High)

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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_