CVE-2023-4366 – This is a use-after-free vulnerability in Googl... (How to Fix)

Q: What is the severity of CVE-2023-4366?

CVE-2023-4366 has a CVSS score of 8.8 (HIGH). This is a use-after-free vulnerability in Google Chrome's extension system that allows heap corruption. Attackers can exploit it by tricking users into installing a malicious extension and then visiting a crafted HTML page. All Chrome users prior to version 116.0.5845.96 are affected.

📋 TL;DR

This is a use-after-free vulnerability in Google Chrome's extension system that allows heap corruption. Attackers can exploit it by tricking users into installing a malicious extension and then visiting a crafted HTML page. All Chrome users prior to version 116.0.5845.96 are affected.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers

Versions: All versions prior to 116.0.5845.96

Operating Systems: Windows, Linux, macOS, Android

Default Config Vulnerable: ⚠️ Yes

Notes: All standard Chrome installations are vulnerable. Requires both malicious extension installation and crafted HTML page visit.

📦 What is this software?

Chrome by Google

Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...

Learn more about Chrome →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full remote code execution leading to complete system compromise, data theft, and persistent backdoor installation.

🟠

Likely Case

Browser crash, extension privilege escalation, or limited code execution within the browser sandbox.

🟢

If Mitigated

No impact if Chrome is updated to patched version or malicious extensions are prevented from installation.

🌐 Internet-Facing: MEDIUM - Requires user interaction (installing extension and visiting malicious page) but can be delivered via phishing.

🏢 Internal Only: LOW - Same requirements apply internally; less likely to be targeted internally.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires social engineering to install malicious extension plus additional user action. No public exploit code available.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 116.0.5845.96 and later

Vendor Advisory: https://chromereleases.googleblog.com/2023/08/stable-channel-update-for-desktop_15.html

Restart Required: Yes

Instructions:

1. Open Chrome. 2. Click three-dot menu → Help → About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' to restart Chrome.

🔧 Temporary Workarounds

Disable extension installation

all

Prevent users from installing extensions to block the initial attack vector

chrome://settings/extensions → Toggle 'Allow extensions from other stores' to OFF

Restrict extension sources

windows

Only allow extensions from Chrome Web Store

Group Policy/Registry: ExtensionInstallSources → Only allow https://chrome.google.com/webstore/*

🧯 If You Can't Patch

Enforce extension allowlisting to prevent malicious extension installation
Implement web filtering to block known malicious HTML pages

🔍 How to Verify

Check if Vulnerable:

Check Chrome version: If version is less than 116.0.5845.96, system is vulnerable.

Check Version:

chrome://version or 'google-chrome --version' on Linux

Verify Fix Applied:

Confirm Chrome version is 116.0.5845.96 or higher after update.

📡 Detection & Monitoring

Log Indicators:

Chrome crash logs with extension-related stack traces
Unexpected extension installation events in system logs

Network Indicators:

Downloads from non-Chrome Web Store extension sources
Requests to known malicious domains hosting crafted HTML

SIEM Query:

source="chrome_logs" AND (event="extension_install" AND source!="chrome.google.com") OR (event="crash" AND process="chrome" AND module="extensions")

📊 Metadata

CVE ID: CVE-2023-4366

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-416

Published: August 15, 2023

Last Updated: November 21, 2024

🔗 References

https://chromereleases.googleblog.com/2023/08/stable-channel-update-for-desktop_15.html Release Notes,Vendor Advisory
https://crbug.com/1450784 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2DMXHPRUGBUDNHZCZCIVMWAUIEXEGMGT/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OCFEK63FUHFXZH5MSG6TNQOXMQWM4M5S/ Mailing List,Third Party Advisory
https://security.gentoo.org/glsa/202401-34
https://www.debian.org/security/2023/dsa-5479 Third Party Advisory
https://chromereleases.googleblog.com/2023/08/stable-channel-update-for-desktop_15.html Release Notes,Vendor Advisory
https://crbug.com/1450784 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2DMXHPRUGBUDNHZCZCIVMWAUIEXEGMGT/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OCFEK63FUHFXZH5MSG6TNQOXMQWM4M5S/ Mailing List,Third Party Advisory
https://security.gentoo.org/glsa/202401-34
https://www.debian.org/security/2023/dsa-5479 Third Party Advisory

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🔗 Related Vulnerabilities

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