Executive Summary

Google has released an emergency security update for its Chrome browser to fix a high-severity vulnerability, CVE-2026-0628. The flaw exists in the WebView component and is caused by "insufficient policy enforcement." This could allow a malicious browser extension to bypass critical security restrictions designed to protect privileged browser pages. Successful exploitation could enable an attacker to steal data, hijack user sessions, or perform other malicious actions. The vulnerability affects Chrome on all major desktop platforms (Windows, macOS, and Linux). Google has not observed any active exploitation but strongly recommends all users update their browsers to version 143.0.7499.192/.193 or later to mitigate the risk.

Vulnerability Details

• CVE ID: CVE-2026-0628
• Severity: High
• Component: WebView
• Description: The vulnerability is categorized as "Insufficient policy enforcement in WebView." The WebView component is a critical part of Chrome and Android that allows applications to render web content. A flaw in its policy enforcement means that security rules that are supposed to isolate content and prevent unauthorized actions can be circumvented.
• Attack Vector: The most likely attack scenario involves social engineering a user into installing a malicious browser extension. Once installed, this extension could leverage CVE-2026-0628 to inject malicious HTML or JavaScript into a privileged context, such as a settings page or another extension's page, which are normally sandboxed and protected.

Exploitation Status: As of the announcement, Google has found no evidence that this vulnerability is being exploited in the wild.

Affected Systems

• Google Chrome: Versions prior to 143.0.7499.192/.193 for Windows, macOS, and Linux.
• Downstream Browsers: Other Chromium-based browsers (e.g., Microsoft Edge, Brave, Opera) are also likely affected and will require updates from their respective vendors.

Impact Assessment

• Security Bypass: The core impact is the bypass of the browser's security model, which is designed to keep web content and extensions isolated from each other and from sensitive parts of the browser.
• Data Theft: An attacker could inject scripts to steal cookies, session tokens, or information entered into forms.
• Session Hijacking: By stealing session cookies, an attacker could potentially take over a user's logged-in sessions for various websites.
• Further Compromise: The ability to execute code in a privileged context could potentially be chained with other vulnerabilities to achieve a more significant system compromise.

Cyber Observables for Detection

Since this vulnerability requires a malicious extension, detection would focus on the delivery and behavior of such extensions.

Detection Methods

• Endpoint Detection and Response (EDR): EDR solutions can monitor for suspicious process behavior originating from the Chrome browser or its extension processes. This could include unexpected file access or network connections.
• Browser Extension Auditing: In an enterprise environment, use browser management tools to maintain an allowlist of approved browser extensions and block users from installing unvetted ones. This is a form of D3FEND Executable Allowlisting (D3-EAL).
• Version Scanning: Use asset management or vulnerability scanning tools to identify all instances of outdated and vulnerable Chrome versions within the organization.

Remediation Steps

1. Update Google Chrome: The only remediation is to ensure all instances of Google Chrome are updated to version 143.0.7499.192/.193 or later. Chrome's auto-update feature will handle this for most users, but it can be forced by navigating to chrome://settings/help.
2. Update Other Chromium Browsers: Users of other Chromium-based browsers should check for and apply updates from their respective vendors.
3. Audit Browser Extensions: Users should review their installed browser extensions (chrome://extensions/) and remove any that are unfamiliar, untrusted, or no longer needed. This reduces the overall attack surface.
4. Enterprise Patch Management: System administrators should use their patch management systems to push the updated Chrome version to all managed endpoints promptly. This is a direct application of D3FEND Software Update (D3-SU).