External risk intelligence

Google Chrome Use After Free Sandbox Escape on macOS

CVE advisorySeverity: CRITICAL (CVSS 9.6)

CVE-2026-11100

This vulnerability affects a client-side web browser. While it requires a remote attacker to provide crafted content, exploitation is contingent upon user interaction (UI gestures) within the browser application itself. It is not a service, gateway, or internet-facing infrastructure component reachable without specific user-driven navigation.

Use After Free

Google Chrome

before 149.0.7827.53

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 for macOS could allow remote attackers to escape the browser's sandbox, potentially leading to broader system compromise if a user interacts with a malicious webpage. This "use after free" flaw in file handling requires specific user actions to exploit, and its impact depends on whether the affected Chrome version is in use.

Flaw allows breaking out of browser security.
Matters if Chrome on Mac is used.
Confirm relevance and exposure to Chrome.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by crafting a malicious HTML page designed to trick a user into interacting with specific elements within their browser. This interaction would trigger a use-after-free condition in the browser's file handling mechanism, potentially allowing the attacker to break out of the browser's sandbox and gain broader access to the system.

Remote attacker, no authentication needed.
User interacts with a malicious webpage.
Risk of sandbox escape and data compromise.

Live Threat

Current exploitation, exposure, and threat context

A use-after-free vulnerability in Chrome's file input handling on macOS could allow a remote attacker to escape the browser's sandbox. This exploitation requires a user to interact with specific UI elements on a specially crafted HTML page.

Sandbox process data could be exposed.
User navigates to a malicious webpage.
Allows potential sandbox escape.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Google Chrome on macOS requires a user to interact with a specially crafted HTML page to trigger a sandbox escape. Real-world responsibility likely falls to application owners managing Chrome deployments and security teams responsible for endpoint protection. The immediate first step is to confirm the presence of the affected Chrome version on endpoints, assess if they are business-critical or user-facing, and then plan remediation, coordinating with end-user support and considering vendor advisories for the correct update path.

Identify affected Chrome instances and owners.
Verify user interaction and exploitability.
Plan for targeted updates and user guidance.

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 and why does this affect macOS users?

Google Chrome is a widely used web browser that renders HTML content and manages file interactions on your computer. This issue is specific to the macOS version of Chrome, where the browser's internal file input handling logic contains a flaw. Because browsers are designed to handle complex files and websites, they maintain deep integration with the underlying operating system, making this specific file-handling error a point of concern for Mac systems.

What does use-after-free mean for CVE-2026-11100?

This is a memory management error classified as CWE-416. It occurs when a program continues to use a memory address after that memory has been cleared or released. In the context of this CVE, the browser accidentally references data that is no longer valid during file input operations. An attacker can manipulate this confusion to run unauthorized instructions, potentially breaking the security sandbox that normally keeps the browser isolated from your computer.

How does an attacker trigger this vulnerability?

An attacker must first entice you to visit a specially crafted HTML webpage. Simply loading the page is not enough; the vulnerability requires you to perform specific UI gestures, such as clicking or interacting with specific file-upload elements. If you do not perform these manual actions on the malicious page, the flaw is not triggered. The vulnerability is entirely dependent on this user-driven interaction within the browser.

Why is this CVE considered relevant to my environment?

This issue is relevant because it affects a client-side application running on your endpoints. According to Halo Surface Signal, the risk is classified as very unlikely for infrastructure because it is not a server-side service or gateway reachable through automated scanning. Instead, it requires a user to actively navigate to a malicious site, meaning the primary concern is for end-user devices rather than backend systems.

What should I do to secure my systems against this threat?

The most effective response is to update Google Chrome to the latest version provided by the vendor. Start by identifying which machines in your environment are running Chrome on macOS, prioritizing systems used for sensitive tasks. Verify their current version number against the patch level mentioned in the official Chrome release notes. Coordinating these updates across your user base will effectively neutralize the flaw 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.