CVE-2026-13948: Google Chrome Auth Bypass Vulnerability

CVE-2026-13948 Overview

CVE-2026-13948 is a user interface (UI) spoofing vulnerability in the Extensions component of Google Chrome versions prior to 150.0.7871.47. The flaw stems from insufficient policy enforcement, which allows a malicious Chrome extension to spoof browser UI elements. An attacker must convince a user to install a crafted extension to exploit the issue. Chromium classifies the security severity as Medium. The weakness maps to [CWE-451: User Interface (UI) Misrepresentation of Critical Information]. Google addressed the issue in the stable channel update for desktop.

Critical Impact
A malicious extension can spoof Chrome UI elements to deceive users into trusting attacker-controlled content, enabling phishing and credential theft scenarios.

Affected Products

Google Chrome for Desktop versions prior to 150.0.7871.47
Chromium-based browsers that inherit the Extensions policy enforcement code path
Any deployment where users can install third-party Chrome extensions

Discovery Timeline

2026-06-30 - CVE-2026-13948 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-13948

Vulnerability Analysis

The vulnerability resides in the Extensions subsystem of Google Chrome. Chrome enforces policies that restrict what extension code may render inside browser-controlled UI surfaces such as the omnibox, permission prompts, and dialog chrome. Insufficient enforcement of those policies lets a crafted extension present content that visually imitates trusted browser UI. Users cannot reliably distinguish spoofed UI from legitimate browser prompts. The issue is tracked in the Chromium Issue Tracker Entry. The CWE-451 classification confirms the impact is misrepresentation of security-critical information rather than memory corruption or code execution. EPSS data reports a low exploitation probability, consistent with the requirement for user-driven extension installation.

Root Cause

The root cause is missing or incomplete policy checks within the Extensions component that governs how extension-rendered content overlaps with browser chrome. The enforcement gap permits an extension to display UI states that should be reserved for the browser itself. This includes spoofing of security indicators, prompts, or origin information that users rely on for trust decisions.

Attack Vector

Exploitation requires social engineering. An attacker publishes or delivers a malicious Chrome extension and persuades a target to install it. Once installed, the extension leverages the enforcement gap to render deceptive UI. The attacker then drives the user toward disclosure of credentials, approval of malicious operations, or execution of attacker-chosen actions. No network-based unauthenticated exploitation path exists without the initial extension installation.

No public proof-of-concept code is available for this vulnerability. Technical specifics remain restricted in the Chromium Issue Tracker at the time of publication.

Detection Methods for CVE-2026-13948

Indicators of Compromise

Chrome browser instances running versions below 150.0.7871.47 on managed endpoints
Recently installed extensions from unofficial sources or sideloaded via developer mode
Extensions requesting broad activeTab, tabs, or <all_urls> host permissions without clear business justification
User reports of unexpected browser prompts, permission dialogs, or address bar behavior following extension installation

Detection Strategies

Inventory installed Chrome extensions across the fleet and compare extension IDs against a known-good allowlist maintained by IT.
Monitor Chrome enterprise policy telemetry for the ExtensionInstallForcelist and ExtensionInstallBlocklist state to detect drift from approved baselines.
Correlate endpoint browser version data with the fixed release 150.0.7871.47 to identify unpatched hosts.
Review Chrome Web Store extension reviews and reputation before allowing installation, and flag extensions with recent ownership changes.

Monitoring Recommendations

Ingest Chrome management logs and extension install events into a centralized logging platform for continuous review.
Track browser update compliance as a security KPI and alert on endpoints that fail to reach the patched build within the maintenance window.
Establish a user reporting channel for suspicious browser prompts so analysts can triage potential spoofing attempts quickly.

How to Mitigate CVE-2026-13948

Immediate Actions Required

Update Google Chrome to version 150.0.7871.47 or later on all managed endpoints, referencing the Google Chrome Stable Update.
Audit currently installed extensions and remove any that are unknown, unused, or sourced outside the Chrome Web Store.
Enforce enterprise extension allowlisting through Chrome policy to block installation of unapproved extensions.
Communicate to users the risk of installing extensions from untrusted publishers and the signs of UI spoofing.

Patch Information

Google released the fix in the Chrome Stable channel build 150.0.7871.47. The update is distributed through the standard Chrome auto-update mechanism and through enterprise deployment tooling such as Chrome Browser Cloud Management. Administrators should validate that endpoints have restarted the browser to complete the update, since Chrome applies staged updates on browser relaunch.

Workarounds

Configure the ExtensionInstallBlocklist policy with a * wildcard and use ExtensionInstallAllowlist to permit only vetted extension IDs.
Disable developer mode extension installation through the DeveloperToolsAvailability policy for standard users.
Restrict extension installation to the Chrome Web Store only via the ExtensionInstallSources policy until patching is complete.

bash

# Configuration example - Chrome enterprise policy (Linux managed_policies path)
# /etc/opt/chrome/policies/managed/extension_control.json
{
  "ExtensionInstallBlocklist": ["*"],
  "ExtensionInstallAllowlist": [
    "<approved-extension-id-1>",
    "<approved-extension-id-2>"
  ],
  "ExtensionInstallSources": [
    "https://chrome.google.com/webstore/*"
  ],
  "DeveloperToolsAvailability": 2
}