External risk intelligence

Chrome for Android Sandbox Escape Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.6)

CVE-2026-118321

The vulnerability affects a web browser client. Exploitation requires a user to navigate to a crafted HTML page, meaning the attack surface is client-side and requires user interaction rather than being a public-facing network service or appliance.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability in Google Chrome on Android, discovered in late October 2026, could allow attackers to execute malicious code outside of the browser's secure environment. This occurs when a user visits a specially crafted webpage, potentially leading to significant compromise if exploited. The main concern is confirming relevance and exposure.

A serious Chrome flaw allows remote code execution.
It affects Android users visiting malicious sites.
Confirm relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

Attack Path

An attacker could leverage an improperly validated input in Google Chrome's Core component on Android to execute arbitrary code outside the browser's sandbox. This would typically involve tricking a user into visiting a malicious HTML page, which then exploits the vulnerability through the browser.

Requires user interaction to visit a crafted page.
Vulnerable component: Core.
Risk: Arbitrary code execution outside sandbox.

Live Threat

Current exploitation, exposure, and threat context

A remote attacker could potentially execute arbitrary code outside the sandbox on an affected Android device by tricking a user into visiting a malicious HTML page. This could compromise the device's security and data.

Device code execution and system compromise.
Visiting a crafted HTML page.
Arbitrary code execution outside sandbox.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Google Chrome on Android requires action from teams managing user endpoints and potentially application owners if custom applications leverage web views. The first critical step is to identify all Android devices running Chrome, assess their exposure, and confirm the business criticality of affected assets before planning the most effective remediation.

Own the endpoint and browser security.
Verify Chrome browser reachability and criticality.
Plan remediation based on identified risk.

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 on Android?

Google Chrome on Android is a widely used mobile web browser that serves as the gateway for accessing internet content. It utilizes a core engine to interpret and render HTML, CSS, and JavaScript. Because it handles diverse web data from untrusted sources, it is designed with a sandbox to isolate browser processes from the rest of the Android operating system, protecting user data and device integrity.

What does improper input validation mean for CVE-2026-118321?

This vulnerability involves a weakness class known as CWE-20, which occurs when a program fails to verify that incoming data is safe or structured as expected. In this case, the browser's core component does not properly check content from a webpage. An attacker can exploit this flaw by sending specifically malformed data that tricks the browser into performing unintended actions, potentially bypassing security boundaries.

How is this Chrome vulnerability triggered?

The attack path relies on a user navigating to a malicious or crafted HTML page using an affected version of Chrome on Android. The bug is not triggered by simply having the browser installed or by passive network activity alone; it requires the user to interact with the web content. If the user does not visit the specifically prepared webpage, the conditions required to exploit this flaw are not met.

Who should be concerned about this Android Chrome flaw?

This vulnerability is relevant to anyone using vulnerable versions of Chrome on Android, as the browser acts as an internet-facing client. According to Halo Surface Signal, this is classified as an external attack surface issue. Because the threat originates from the internet and requires user navigation, the risk is concentrated on mobile endpoints where users frequently access diverse, uncontrolled web content.

What should I do if my devices are running an affected Chrome version?

Your first step is to locate all Android devices in your environment that are running the vulnerable Chrome software. Assess these assets based on their business use and identify which users are frequently accessing public web content. Once you have an inventory, prepare to update the browser application to the secure version provided by Google to close the sandbox escape risk.

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.