Origin CyberAnatomy Spoofing via Malicious WebView - Dissecting CVE-2026-0628 Chromium Extension Privilege Escalation

Origin CyberAnatomy Spoofing via Malicious WebView - Dissecting CVE-2026-0628 Chromium Extension Privilege Escalation

This research provides a comprehensive technical dissection of CVE-2026-0628, a high-severity privilege escalation vulnerability (CVSS v3.1: 8.8) in Chromium's WebView policy enforcement mechanism. The vulnerability enables malicious extensions to bypass sandbox isolation and execute arbitrary code within privileged browser contexts, such as chrome:// and chrome-extension:// pages, by exploiting insufficient validation in the Mojo IPC (Inter-Process Communication) protocol.

Core Vulnerability Mechanics

1. Root Cause: A logic flaw in Chromium's WebViewPolicyValidator::ValidateRequest() function allows origin spoofing and privilege escalation. The function fails to validate whether an extension has sufficient permissions to access privileged origins, such as chrome://settings or chrome-extension://background. Attackers exploit this by crafting malicious WebView elements with attributes like nodeintegration and allowpopups, which bypass security checks and grant access to high-privilege contexts.

2. Exploit Chain:

   • Malicious Extension Deployment: An attacker tricks a user into installing an extension with a crafted manifest that declares WebView usage and broad permissions.
   • WebView Injection: The extension dynamically injects a hidden WebView element (<webview src="chrome://new-tab-page/">) into a webpage.
   • Privilege Escalation: The WebView bypasses policy validation and executes arbitrary JavaScript in a privileged context, enabling data theft (e.g., cookies, localStorage, session tokens) and lateral movement within the browser.
   • Sandbox Escape: On Microsoft Edge, the exploit can be chained with token duplication techniques to escape the browser sandbox and execute code at Medium Integrity Level (IL), potentially leading to full system compromise.

3. Impact:

   • Confidentiality: High (theft of sensitive data, such as cookies and session tokens).
   • Integrity: High (manipulation of browser settings and extensions).
   • Availability: High (persistent background scripts for C2 beaconing).
   • Attack Vector: Network-based (requires user interaction to install the extension).