External risk intelligence

Chrome V8 Sandbox Escape via Crafted HTML

CVE advisoryKnown Exploit

CVE-2026-11645

A vulnerability in Google Chrome's V8 engine allows a remote attacker to execute arbitrary code via a crafted HTML page. This could compromise browser sandbox integrity, impacting systems that use this web browser technology.

3Halo Surface Signal

Out-of-bounds Read

Google Chrome

before 149.0.7827.103

External exposure likelihood

Halo Surface Signal score for CVE-2026-11645

The vulnerability exists in the V8 engine within web browsers, requiring a user to visit a crafted HTML page. While web browsers are internet-facing applications, this specific attack surface relies on user-initiated navigation to malicious content rather than a public-facing service or appliance listening for incoming connections.

PCI scan relevance

PCI Relevance for CVE-2026-11645

Yes

CVE-2026-11645 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

This CVE is PCI scan-relevant due to a critical vulnerability in Google Chrome's V8 engine that allows remote code execution within a sandbox, which could lead to a scan failure.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a high-severity vulnerability in the V8 JavaScript engine used in Google Chrome. The issue allows a remote attacker to potentially execute arbitrary code within a protected environment by tricking a user into visiting a specially crafted webpage. This could have significant implications for systems relying on this browser technology for web interactions.

Vulnerability allows code execution via malicious web pages.
Affects widespread browser technology, warranting attention.
Confirm relevance and assess exposure to potential impact.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by luring a user to a specially crafted webpage. This page would then interact with a vulnerable component within the browser's JavaScript engine. If successful, the attacker could achieve arbitrary code execution within the browser's sandbox, potentially leading to further system compromise.

Requires user to visit malicious page.
Triggered by crafted HTML and JavaScript.
Risk of arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

A remote attacker could execute arbitrary code inside a sandbox when supported by the advisory, by tricking a user into visiting a malicious HTML page. This could affect web browsers that use the V8 engine, potentially impacting the integrity of the user's session within the browser.

Browser sandbox integrity could be compromised.
Via a crafted HTML page presented to a user.
Arbitrary code execution inside the sandbox.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Google Chrome's V8 engine requires identifying affected systems, confirming their exposure and criticality, and then coordinating remediation. The first practical step is to locate all instances of the affected Chrome version, determine which are reachable externally or handle sensitive data, and assign ownership for risk assessment and planned updates.

Ownership: Application or browser owners must act.
Verify: Confirm browser reachability and criticality.
Action: Plan updates during maintenance windows.

Frequently asked questions

What is the V8 engine in Google Chrome?

V8 is the high-performance JavaScript and WebAssembly engine that powers Google Chrome and many other Chromium-based browsers. It is responsible for interpreting and executing the complex code that makes modern websites interactive. When you visit a webpage, V8 processes the site's scripts to render content, making it a critical component for both browser functionality and overall system security.

What does out-of-bounds read and write mean for CVE-2026-11645?

This vulnerability involves two common memory errors: CWE-125 (Out-of-Bounds Read) and CWE-787 (Out-of-Bounds Write). Essentially, the software fails to properly check memory boundaries when processing data, allowing it to access or overwrite information outside of its allocated space. In this CVE, an attacker uses this flaw to manipulate the V8 engine's memory, potentially running malicious code.

How does an attacker trigger this vulnerability?

An attacker triggers this flaw by luring a user to visit a specially crafted HTML page containing malicious scripts. The vulnerability is not triggered by simply having the browser installed; it requires the user to actively navigate to the malicious content. Normal, benign web browsing does not initiate this process, as it specifically depends on the browser processing the attacker's malformed code.

Is this CVE a risk for my systems?

Halo Surface Signal notes that while browsers are internet-facing, this vulnerability is not a traditional network service attack. Because it requires a user to visit a malicious site, the risk is highest for users frequently navigating untrusted web content. Assessing your exposure involves identifying systems where Chrome handles sensitive data or provides administrative access to internal tools.

What is the first step to address CVE-2026-11645?

The primary response is to identify all installations of Chrome versions prior to 149.0.7827.103 within your environment. Once located, coordinate with browser owners to plan and deploy the stable channel update provided by Google. Prioritize updates for workstations that handle sensitive data or have broad access to internal network resources to minimize potential impact.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.