CVE-2026-6299: Google Chrome Use-After-Free Vulnerability

CVE-2026-6299 Overview

CVE-2026-6299 is a use-after-free vulnerability in the Prerender component of Google Chrome prior to version 147.0.7727.101. This memory corruption flaw allows a remote attacker to execute arbitrary code by tricking a user into visiting a maliciously crafted HTML page. Chromium has rated this vulnerability as critical in severity.

Critical Impact

Successful exploitation enables remote code execution on affected systems, potentially allowing attackers to gain complete control over the victim's browser session and execute malicious payloads with the user's privileges.

Affected Products

• Google Chrome versions prior to 147.0.7727.101
• Chromium-based browsers using affected Prerender component
• Desktop installations across Windows, macOS, and Linux platforms

Discovery Timeline

• April 15, 2026 - CVE-2026-6299 published to NVD
• April 15, 2026 - Last updated in NVD database

Technical Details for CVE-2026-6299

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of Chrome's Prerender feature, this creates a dangerous condition where freed memory can be reallocated and manipulated by an attacker.

The Prerender component is designed to improve page load performance by pre-rendering pages that users are likely to visit. However, the vulnerable code path allows an attacker to trigger a condition where memory associated with a prerendered page is freed while still being referenced, creating an exploitable use-after-free condition.

Remote exploitation is possible via the network, requiring only that a victim navigate to an attacker-controlled web page. No authentication or special privileges are required for the attack to succeed, though user interaction (visiting the malicious page) is necessary.

Root Cause

The root cause stems from improper memory lifecycle management within the Prerender subsystem. When certain page navigation events occur during the prerendering process, object references can become desynchronized from their underlying memory allocations. This results in dangling pointers that continue to be dereferenced after the associated memory has been freed and potentially reallocated for other purposes.

Attack Vector

The attack vector is network-based, requiring the victim to visit a specially crafted HTML page. An attacker would typically:

1. Create a malicious web page containing HTML/JavaScript designed to trigger the vulnerable code path in Chrome's Prerender component
2. Distribute the malicious link via phishing emails, social engineering, malicious advertisements, or compromised websites
3. When a victim visits the page with a vulnerable Chrome version, the exploit triggers the use-after-free condition
4. The attacker's payload executes arbitrary code within the context of the browser process

The vulnerability requires user interaction but has low attack complexity. Once triggered, the attacker can achieve code execution with the same privileges as the Chrome browser process.

Detection Methods for CVE-2026-6299

Indicators of Compromise

• Unexpected Chrome browser crashes or instability when visiting unknown websites
• Anomalous process behavior spawned from Chrome browser processes
• Suspicious network connections originating from Chrome to unknown command-and-control infrastructure
• Memory dumps showing heap corruption patterns consistent with use-after-free exploitation

Detection Strategies

• Monitor Chrome browser version across endpoints and flag installations running versions prior to 147.0.7727.101
• Deploy endpoint detection and response (EDR) solutions capable of detecting memory corruption exploitation techniques
• Implement network monitoring to identify connections to known malicious domains or suspicious post-exploitation traffic
• Enable Chrome's built-in crash reporting and monitor for patterns indicating exploitation attempts

Monitoring Recommendations

• Configure centralized logging to capture Chrome browser events and crash reports
• Implement behavioral analysis to detect unusual child process creation from browser processes
• Monitor for JavaScript execution patterns consistent with heap spraying or other memory manipulation techniques
• Track DNS queries and network connections from browser processes for anomalous activity

How to Mitigate CVE-2026-6299

Immediate Actions Required

• Update Google Chrome to version 147.0.7727.101 or later immediately across all endpoints
• Verify Chrome's automatic update mechanism is functioning properly on all managed devices
• Conduct an inventory scan to identify any systems running vulnerable Chrome versions
• Consider temporarily restricting access to untrusted websites until patching is complete

Patch Information

Google has released Chrome version 147.0.7727.101 which addresses this vulnerability. The update is available through Chrome's built-in automatic update mechanism. Organizations should verify that all Chrome installations have been updated by checking the browser version via chrome://version.

For detailed information about the security update, refer to the Google Chrome Update Announcement. Additional technical details may be found in the Chromium Issue Tracker Entry.

Workarounds

• If immediate patching is not possible, consider disabling the Prerender feature via Chrome enterprise policies
• Implement strict browsing policies to limit access to untrusted websites
• Deploy browser isolation solutions to contain potential exploitation attempts
• Use network-level filtering to block access to known malicious sites while awaiting patch deployment

# Configuration example - Chrome Enterprise Policy to disable prerender
# Create or edit the Chrome policy JSON file

# On Linux: /etc/opt/chrome/policies/managed/prerender_policy.json
# On macOS: /Library/Google/GoogleSoftwareUpdate/GoogleUpdate.plist
# On Windows: Use Group Policy Editor or registry

# Example policy JSON to disable network predictions (includes prerender):
{
  "NetworkPredictionOptions": 2
}

# Value 2 = Never predict network actions (disables prerender)