---
id: "CVE-2026-121103"
kind: "vulnerability"
aliases: ["CVE-2026-121103"]
title: "Chrome: extension authorization flaw lets a site read cross-origin data"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["browser", "chrome", "desktop", "package"]
not_affected_if: ["chrome-157-or-later"]
published_at: "2026-11-03T21:17:16+00:00"
first_seen_at: "2026-11-03T21:19:14+00:00"
updated_at: "2026-11-03T21:25:16+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121103", "first_seen_at": "2026-11-03T21:19:14+00:00"}]
---

# Chrome: extension authorization flaw lets a site read cross-origin data

Google Chrome versions before 157.0.8103.38 have an incorrect authorization bug in extensions. A remote attacker can use a crafted Chrome extension to obtain data from other origins.

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

## How to check

- Check the installed Chrome version at chrome://settings/help and compare it with `157.0.8103.38`
- Review which extensions are installed at chrome://extensions

## Fix

- Google Chrome: move to `157.0.8103.38` or later

## Timeline

- 2026-11-03T21:19:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121103

## From the sources

Incorrect authorization in Extensions in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to obtain cross-origin data 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_