CVE-2026-6307: Google Chrome Turbofan RCE Vulnerability

CVE-2026-6307 Overview

A type confusion vulnerability exists in the Turbofan JavaScript compiler component of Google Chrome prior to version 147.0.7727.101. This flaw allows a remote attacker to execute arbitrary code within the browser's sandbox by convincing a user to visit a specially crafted HTML page. The vulnerability stems from improper type handling during JavaScript Just-In-Time (JIT) compilation, which can lead to memory corruption and subsequent code execution.

Critical Impact

Remote code execution within the Chrome sandbox through a malicious webpage, potentially leading to further exploitation when combined with sandbox escape vulnerabilities.

Affected Products

• Google Chrome versions prior to 147.0.7727.101
• Chromium-based browsers using affected Turbofan engine versions
• All platforms running vulnerable Chrome versions (Windows, macOS, Linux)

Discovery Timeline

• 2026-04-15 - CVE-2026-6307 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-6307

Vulnerability Analysis

This vulnerability is classified as CWE-843 (Access of Resource Using Incompatible Type, or 'Type Confusion'). Type confusion vulnerabilities in JavaScript engines like Turbofan occur when the JIT compiler makes incorrect assumptions about object types during optimization passes. When these assumptions are violated at runtime, the engine may access memory using an incorrect type interpretation, leading to memory corruption.

In Turbofan, the optimizing compiler performs speculative optimizations based on observed type feedback. When the compiler incorrectly predicts an object's type and generates optimized machine code based on that assumption, an attacker can craft JavaScript that violates these assumptions, causing the compiled code to operate on data with an unexpected memory layout.

Root Cause

The root cause lies in Turbofan's type inference and optimization pipeline. During JIT compilation, Turbofan builds an intermediate representation of JavaScript code and applies various optimization phases. When type guards are insufficient or incorrectly placed, the resulting compiled code may access object properties at memory offsets that are only valid for the expected type, not the actual type provided at runtime. This type mismatch enables attackers to achieve controlled memory corruption.

Attack Vector

The attack is network-based and requires user interaction—specifically, the victim must navigate to a malicious webpage containing crafted JavaScript. The attacker hosts or injects malicious JavaScript that triggers the type confusion condition in Turbofan. Upon successful exploitation, arbitrary code executes within Chrome's renderer sandbox. While sandbox containment provides defense-in-depth, this vulnerability could be chained with sandbox escape exploits for full system compromise.

The attack flow typically involves:

1. Victim visits attacker-controlled or compromised webpage
2. Malicious JavaScript triggers JIT compilation with specific type patterns
3. Subsequent code execution violates compiler's type assumptions
4. Type confusion leads to memory corruption enabling code execution

For detailed technical information, refer to the Chromium Issue Tracker Entry and the Google Chrome Update Announcement.

Detection Methods for CVE-2026-6307

Indicators of Compromise

• Unusual Chrome renderer process crashes or unexpected process terminations
• Detection of known malicious JavaScript patterns associated with JIT exploitation techniques
• Network traffic to domains hosting known exploit kits targeting Chrome vulnerabilities
• Anomalous memory access patterns within Chrome renderer processes

Detection Strategies

• Monitor for Chrome renderer process crashes with signatures consistent with type confusion exploitation
• Deploy endpoint detection rules for JavaScript obfuscation techniques commonly used in browser exploits
• Implement network-level detection for known exploit kit landing pages and malicious domains
• Enable Chrome's built-in crash reporting and monitor for patterns indicating active exploitation attempts

Monitoring Recommendations

• Enable enhanced logging for browser processes to capture crash dump information
• Monitor endpoint telemetry for suspicious Chrome child process behavior
• Track browser version inventory across the organization to identify unpatched systems
• Implement web proxy logging to identify access to potentially malicious domains

How to Mitigate CVE-2026-6307

Immediate Actions Required

• Update Google Chrome to version 147.0.7727.101 or later immediately
• Enable automatic Chrome updates to ensure timely patching of future vulnerabilities
• Review and update Chromium-based applications (Electron apps, Edge, etc.) that may be affected
• Implement browser isolation solutions for high-risk users until patching is complete

Patch Information

Google has released Chrome version 147.0.7727.101 which addresses this type confusion vulnerability in Turbofan. Organizations should prioritize deployment of this update across all managed endpoints. For detailed patch information, see the Google Chrome Update Announcement.

Workarounds

• Enable Chrome's Site Isolation feature to provide additional process-level separation
• Consider temporarily disabling JavaScript on untrusted sites using browser extensions or enterprise policies
• Implement web filtering to block access to known malicious domains and suspicious URLs
• Deploy browser isolation solutions to execute web content in isolated environments

# Force Chrome update via command line (Windows)
# Check current Chrome version and trigger update
"C:\Program Files\Google\Chrome\Application\chrome.exe" --version

# Enterprise deployment: Use Chrome Browser Cloud Management or GPO
# Set update policy to force automatic updates
# Registry key: HKLM\SOFTWARE\Policies\Google\Update
# Set "Update{8A69D345-D564-463C-AFF1-A69D9E530F96}" to 1 (Always update)