CVE-2021-4067 – This is a use-after-free vulnerability in Chrom... (How to Fix)

Q: What is the severity of CVE-2021-4067?

CVE-2021-4067 has a CVSS score of 8.8 (HIGH). This is a use-after-free vulnerability in ChromeOS's window manager that allows remote attackers to potentially exploit heap corruption via a crafted HTML page. Attackers could execute arbitrary code or cause denial of service. Users of ChromeOS with Chrome versions prior to 96.0.4664.93 are affected.

📋 TL;DR

This is a use-after-free vulnerability in ChromeOS's window manager that allows remote attackers to potentially exploit heap corruption via a crafted HTML page. Attackers could execute arbitrary code or cause denial of service. Users of ChromeOS with Chrome versions prior to 96.0.4664.93 are affected.

💻 Affected Systems

Products:

Google Chrome
ChromeOS

Versions: Chrome versions prior to 96.0.4664.93

Operating Systems: ChromeOS, Linux, Windows, macOS

Default Config Vulnerable: ⚠️ Yes

Notes: Affects Chrome browser on all platforms, but specifically mentions ChromeOS window manager. All default configurations are vulnerable.

📦 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

Remote code execution leading to full system compromise, data theft, or persistent malware installation.

🟠

Likely Case

Browser crash/denial of service or limited code execution within Chrome's sandbox.

🟢

If Mitigated

No impact if patched; Chrome's sandbox may limit damage if exploited.

🌐 Internet-Facing: HIGH - Remote exploitation via crafted web pages.

🏢 Internal Only: MEDIUM - Requires user interaction with malicious content.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Requires user to visit malicious webpage. Use-after-free vulnerabilities often lead to reliable exploitation.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 96.0.4664.93 and later

Vendor Advisory: https://chromereleases.googleblog.com/2021/12/stable-channel-update-for-desktop.html

Restart Required: Yes

Instructions:

1. Open Chrome browser. 2. Click menu (three dots) > Help > About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' to restart Chrome with the update.

🔧 Temporary Workarounds

Disable JavaScript

all

Prevents execution of malicious JavaScript that could trigger the vulnerability.

chrome://settings/content/javascript

Use Site Isolation

all

Enhances Chrome's sandboxing to limit impact if exploited.

chrome://flags/#enable-site-per-process

🧯 If You Can't Patch

Restrict access to untrusted websites using web filtering or proxy controls.
Implement application whitelisting to prevent unauthorized code execution.

🔍 How to Verify

Check if Vulnerable:

Check Chrome version: If version is less than 96.0.4664.93, system is vulnerable.

Check Version:

google-chrome --version

Verify Fix Applied:

Confirm Chrome version is 96.0.4664.93 or higher after update.

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports
Unexpected process termination logs
Security event logs showing exploit attempts

Network Indicators:

Requests to known malicious domains hosting exploit code
Unusual outbound connections from Chrome processes

SIEM Query:

source="chrome" AND (event_type="crash" OR process_name="chrome.exe") AND version<"96.0.4664.93"

📊 Metadata

CVE ID: CVE-2021-4067

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: December 23, 2021

Last Updated: November 21, 2024

🔗 References

https://chromereleases.googleblog.com/2021/12/stable-channel-update-for-desktop.html Vendor Advisory
https://crbug.com/1274641 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3W46HRT2UVHWSLZB6JZHQF6JNQWKV744/
https://security.gentoo.org/glsa/202208-25 Third Party Advisory
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory
https://chromereleases.googleblog.com/2021/12/stable-channel-update-for-desktop.html Vendor Advisory
https://crbug.com/1274641 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3W46HRT2UVHWSLZB6JZHQF6JNQWKV744/
https://security.gentoo.org/glsa/202208-25 Third Party Advisory
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory

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