CVE-2026-11308: Google Chrome Privilege Escalation Flaw

CVE-2026-11308 Overview

CVE-2026-11308 affects Google Chrome versions prior to 149.0.7827.53. The vulnerability stems from an inappropriate implementation in the Chrome Extensions component. An attacker who convinces a user to install a malicious extension can perform privilege escalation through a crafted Chrome Extension. The flaw is tracked as [CWE-269] (Improper Privilege Management) and impacts Chrome installations on Windows, macOS, and Linux. Chromium classifies the security severity as Low, while NVD scores the issue at 6.3 (Medium).

Critical Impact
A crafted Chrome Extension can escalate privileges within the browser, allowing an attacker to perform actions beyond those normally permitted to extensions once a user is convinced to install it.

Affected Products

Google Chrome versions prior to 149.0.7827.53
Chrome installations on Microsoft Windows, Apple macOS, and Linux
Browser environments allowing user-installed extensions from any source

Discovery Timeline

2026-06-05 - CVE-2026-11308 published to NVD
2026-06-08 - Last updated in NVD database

Technical Details for CVE-2026-11308

Vulnerability Analysis

The vulnerability resides in the Extensions subsystem of Google Chrome. Chrome Extensions operate within a privilege model that limits the actions an extension can perform on the browser, web content, and the underlying system. CVE-2026-11308 reflects an inappropriate implementation that fails to correctly enforce these privilege boundaries.

A malicious extension crafted to exploit this flaw can elevate the privileges it operates with inside the browser. This allows the extension to perform operations that should be restricted by Chrome's extension permission model. The vulnerability requires user interaction, since the user must be convinced to install the malicious extension first.

The issue affects the browser process and renderer interactions that handle extension-granted capabilities. Additional context is available in the Chromium Issue Tracker Entry.

Root Cause

The root cause is improper privilege management ([CWE-269]) in the Extensions component. Chrome did not adequately enforce constraints on what a crafted extension could request or execute, enabling the extension to operate beyond its intended privilege scope.

Attack Vector

The attack vector is network-based with required user interaction. An attacker must distribute a malicious extension, typically through the Chrome Web Store, third-party stores, or sideloading prompts, and convince the user to install it. Once installed, the extension exercises the privilege escalation primitive without further user action. No additional authentication is required by the attacker.

No public proof-of-concept or in-the-wild exploitation has been reported. The EPSS score is 0.017%, reflecting low predicted exploitation activity.

No verified exploit code is available for this CVE. Refer to the Chromium Issue Tracker Entry and the Google Chrome Stable Update for vendor details.

Detection Methods for CVE-2026-11308

Indicators of Compromise

Installation of Chrome extensions from outside the official Chrome Web Store or from unverified publishers.
Chrome browser versions reporting below 149.0.7827.53 in enterprise inventory data.
Extension manifest files requesting unusual permission combinations or unexpected host permissions.
Outbound network traffic from chrome.exe to suspicious domains correlated with recently installed extensions.

Detection Strategies

Audit installed Chrome extensions across managed endpoints and compare against an allowlist of approved IDs.
Monitor changes to the Chrome Extensions directory under each user profile for new or modified extension packages.
Inspect extension manifests (manifest.json) for permissions, host_permissions, and content_scripts entries that exceed business need.
Correlate extension installation events with subsequent browser process behavior such as new child processes or registry modifications.

Monitoring Recommendations

Enforce Chrome version reporting through enterprise management and alert on hosts running versions earlier than 149.0.7827.53.
Track Chrome update telemetry to confirm patch propagation across the fleet.
Log and review Chrome enterprise policy events related to ExtensionInstallBlocklist and ExtensionInstallAllowlist.

How to Mitigate CVE-2026-11308

Immediate Actions Required

Update Google Chrome to version 149.0.7827.53 or later on all Windows, macOS, and Linux endpoints.
Verify automatic update functionality is enabled and not blocked by network or policy configurations.
Review currently installed extensions and remove any that are unused, unknown, or from untrusted publishers.
Restrict extension installation to an enterprise-managed allowlist using Chrome policy.

Patch Information

Google released the fix in Chrome Stable channel version 149.0.7827.53. Details are documented in the Google Chrome Stable Update advisory. Administrators should validate that all managed Chrome installations reflect this build or newer.

Workarounds

Apply the ExtensionInstallBlocklist policy with a value of * to block all extensions, then explicitly allowlist required extension IDs through ExtensionInstallAllowlist.
Configure ExtensionInstallSources to restrict where extensions may be installed from.
Educate users to install extensions only from verified publishers and to review requested permissions before approval.
Disable developer mode in Chrome to prevent sideloading of unpacked extensions on managed endpoints.

bash

# Chrome enterprise policy example (Windows registry)
reg add "HKLM\Software\Policies\Google\Chrome\ExtensionInstallBlocklist" /v 1 /t REG_SZ /d "*" /f
reg add "HKLM\Software\Policies\Google\Chrome\ExtensionInstallAllowlist" /v 1 /t REG_SZ /d "<approved-extension-id>" /f