---
id: "CVE-2026-121248"
kind: "vulnerability"
aliases: ["CVE-2026-121248"]
title: "Google Chrome: API authorization flaw lets crafted extension bypass system access restrictions"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["browsers", "chrome", "desktop", "runtime"]
not_affected_if: ["chrome-at-or-above-157.0.8103.38", "extension-installs-blocked"]
published_at: "2026-11-03T21:17:35+00:00"
first_seen_at: "2026-11-03T21:19:29+00:00"
updated_at: "2026-11-03T21:21:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121248", "first_seen_at": "2026-11-03T21:19:29+00:00"}]
---

# Google Chrome: API authorization flaw lets crafted extension bypass system access restrictions

An incorrect authorization check in a Chrome API lets a crafted Chrome extension bypass system access restrictions. The attacker gets access the browser is meant to block, and the source rates it Medium severity in Chromium.

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

## How to check

- Check the Chrome version in the browser's About page or with `google-chrome --version` on Linux; versions below `157.0.8103.38` are affected.
- Review installed extensions for unfamiliar or unnecessary ones.

## Fix

- Google Chrome: update to `157.0.8103.38` or later.

## Timeline

- 2026-11-03T21:19:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121248

## From the sources

Incorrect authorization in API in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to bypass system access restrictions via a crafted Chrome extension. (Chromium security severity: Medium)

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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_