External risk intelligence

Google Chrome WebNN Sandbox Escape Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.6)

CVE-2026-11063

The vulnerability affects a web browser, which is an internet-facing client application designed to process untrusted content from the web. By design, browsers are exposed to public network traffic and rely on rendering engines to process external HTML/scripts, making this component a common vector for remote exploitation during normal web browsing activities.

Google Chrome

before 149.0.7827.53

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in Google Chrome on Windows that could allow a remote attacker to escape the browser's security sandbox. This occurs due to insufficient validation of untrusted input within the WebNN component when a user visits a specially crafted web page.

Input validation flaw in browser.
Could allow attackers to bypass security.
Confirm if affected by this browser flaw.

Attack Path

How an attacker could exploit the issue

An attacker could trick a user into visiting a malicious webpage, which then targets a vulnerability in the Chrome browser's WebNN component. This could allow the attacker to break out of the browser's sandbox, potentially leading to broader system compromise.

Entry condition: User visits a malicious webpage.
Trigger point: Vulnerability in WebNN component.
Resulting risk: Sandbox escape.

Live Threat

Current exploitation, exposure, and threat context

A sandbox escape, when supported by the advisory, could allow an attacker to access or modify system files and execute arbitrary code on a Windows machine. This could occur if a user visits a specially crafted HTML page while running a vulnerable version of Google Chrome.

System files and code execution.
Visiting a malicious HTML page.
Compromise of the affected system.

Operational Fix

Recommended remediation, mitigation, and detection steps

This CVE impacts Google Chrome on Windows, making the platform team and the security operations center (SOC) key responders. The initial step is to identify all Windows endpoints running Chrome, determine their internet-facing exposure and business criticality, and confirm the accountable owner for remediation.

Platform and security teams own this.
Verify internet-exposed Windows endpoints.
Plan targeted updates or vendor coordination.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Google Chrome's WebNN component?

WebNN, or Web Neural Network API, is a component in Chrome that allows websites to run machine learning tasks directly on your computer's hardware. By leveraging your device's processors, it enables features like real-time image processing or AI-driven tools within the browser. Because it handles complex data from web pages, it acts as a bridge between the browser's isolated environment and your local system's capabilities.

How does CVE-2026-11063 create a security risk?

This vulnerability is classified as CWE-20, which relates to improper input validation. Essentially, the WebNN component fails to thoroughly check the data it receives from a web page. If the data is malicious, the browser might misinterpret it, allowing an attacker to bypass security boundaries meant to keep the website contained. This flaw in processing untrusted input is what potentially leads to a sandbox escape.

Does just having Chrome installed trigger this vulnerability?

No, simply having the browser installed is not enough to trigger the issue. An attacker must successfully lure a user into visiting a specifically crafted, malicious HTML page while using an outdated version of Chrome. If you do not navigate to the malicious site, the vulnerable code path in WebNN is not engaged.

Why is this CVE considered relevant for my Windows systems?

Halo Surface Signal identifies this as an external-facing risk because browsers are designed to constantly fetch and render untrusted content from the internet. Since Chrome runs on Windows and processes external traffic by default, it is positioned at the edge of your network. If the sandbox is breached, the attacker could theoretically move from the browser environment to the underlying operating system.

What is the first step to address CVE-2026-11063?

The most effective response is to update Google Chrome on all Windows devices to version 149.0.7827.53 or later. This update includes the necessary patches to fix the input validation logic within WebNN. Start by inventorying your Windows endpoints to identify those running older versions of the browser and prioritize them for the update process.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.