---
id: CVE-2025-9866
title: >-
  Inappropriate implementation in Extensions in Google Chrome prior to
  140.0.7339.80 allowed a remote attacker to bypass content security policy via
  a crafted HTML page
summary: >-
  Inappropriate implementation in Extensions in Google Chrome prior to
  140.0.7339.80 allowed a remote attacker to bypass content security policy via
  a crafted HTML page. (Chromium security severity: Medium)
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-693
vendor: google
product: chrome
affected:
  - chrome < 140.0.7339.80
patched:
  - chrome 140.0.7339.80
published: '2025-09-03'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T00:10:00.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-9866'
references:
  - url: >-
      https://chromereleases.googleblog.com/2025/09/stable-channel-update-for-desktop.html
    label: chrome-cve-admin@google.com
  - url: 'https://issues.chromium.org/issues/379337758'
    label: chrome-cve-admin@google.com
tags:
  - nvd
epss: 0.00364
epssPercentile: 0.27555
ingestedAt: '2026-09-26T00:22:39.908Z'
---

## Overview

Inappropriate implementation in Extensions in Google Chrome prior to 140.0.7339.80 allowed a remote attacker to bypass content security policy via a crafted HTML page. (Chromium security severity: Medium)

## Affected

- `chrome < 140.0.7339.80`

## Remediation

Upgrade past the affected range:

- `chrome 140.0.7339.80`