External risk intelligence

Chrome iOS WebMIDI Sandbox Escape

CVE advisorySeverity: CRITICAL (CVSS 9.6)

CVE-2026-11165

The vulnerability exists in a widely used web browser, which is designed to process external web content. Because web browsers are routinely used to navigate public internet sites and process untrusted remote HTML, they are fundamentally internet-facing applications.

Use After Free

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 security flaw in Chrome for iOS could allow attackers to escape the browser's security boundaries through malicious web pages. This vulnerability is rated critical and affects a widely used browser, increasing the potential for misuse. The primary concern is to confirm if our environment is exposed to this type of attack.

Flaw in Chrome for iOS allows malicious web page access.
Matters because browsers process untrusted web content.
Confirm relevance and exposure to this threat.

Attack Path

How an attacker could exploit the issue

An attacker could lure a user to a malicious website using a specially crafted HTML page. If the user visits this page, the vulnerability in Chrome's WebMIDI component on iOS could allow the attacker to break out of the browser's sandbox, potentially leading to broader system compromise.

Requires visiting a malicious website.
Triggered by user interaction with a crafted page.
Risk of sandbox escape.

Live Threat

Current exploitation, exposure, and threat context

A remote attacker could potentially gain elevated privileges by tricking a user into visiting a malicious webpage, enabling them to escape the browser's sandbox environment.

Browser sandbox escape.
Via a crafted HTML page.
Unspecified system compromise.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts Google Chrome on iOS, making the platform or browser owners responsible for remediation. The first practical step is to identify all iOS devices running Chrome, confirm reachability and business criticality, and then plan for updates or mitigations.

Platform/browser owners should address.
Verify Chrome on iOS installations.
Plan for updates and mitigations.

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 iOS and its WebMIDI component?

Google Chrome for iOS is a widely used mobile web browser that allows users to access the internet. WebMIDI is a feature within the browser designed to enable communication with MIDI devices like synthesizers or controllers directly through a webpage. This component extends browser functionality by interacting with external hardware interfaces, which introduces complex code paths that must be carefully managed to maintain security.

What does CWE-416 mean for CVE-2026-11165?

CWE-416 refers to a 'Use After Free' vulnerability. In plain language, this means the software continues to use a piece of memory after it has been cleared or deleted. In the context of CVE-2026-11165, this memory management error in the WebMIDI component can create an unstable state that an attacker might manipulate to bypass the browser's security controls, potentially leading to unauthorized actions outside the intended environment.

How is this Chrome vulnerability triggered?

An attacker triggers this flaw by luring a user to a specially crafted HTML page. The vulnerability is activated when the browser attempts to process the malicious code within that page. Simply having Chrome installed is not enough; the bug does not trigger unless the user actively navigates to a site designed to exploit the WebMIDI memory error. It relies on the browser's normal function of loading and executing external content.

Why should I care about this vulnerability?

According to Halo Surface Signal, this vulnerability is highly relevant because web browsers are designed to process untrusted content from the public internet. Because users frequently navigate to various websites, they are naturally exposed to potential threats. Since Chrome is an internet-facing application, its components must maintain robust isolation to prevent a web-based attack from escalating into a system-level compromise.

How do I respond to CVE-2026-11165?

The most effective response is to update the Chrome browser on all affected iOS devices to version 149.0.7827.53 or later, which includes the fix for this issue. You should start by auditing your environment to identify which devices are running outdated versions of Chrome. Once identified, ensure these devices are updated through the standard app update process to remove the vulnerability and restore the browser's sandbox protections.

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.