CVE-2020-6548 – This vulnerability is a heap buffer overflow in... (How to Fix)

Q: What is the severity of CVE-2020-6548?

CVE-2020-6548 has a CVSS score of 8.8 (HIGH). This vulnerability is a heap buffer overflow in the Skia graphics library used by Google Chrome. It allows a remote attacker who has already compromised the renderer process to potentially exploit heap corruption via a crafted HTML page, which could lead to arbitrary code execution. Users of affected Chrome versions are at risk.

📋 TL;DR

This vulnerability is a heap buffer overflow in the Skia graphics library used by Google Chrome. It allows a remote attacker who has already compromised the renderer process to potentially exploit heap corruption via a crafted HTML page, which could lead to arbitrary code execution. Users of affected Chrome versions are at risk.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers

Versions: Versions prior to 84.0.4147.125

Operating Systems: Windows, Linux, macOS, Android, iOS

Default Config Vulnerable: ⚠️ Yes

Notes: All default Chrome configurations are vulnerable. The vulnerability requires the attacker to first compromise the renderer process.

📦 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...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise via arbitrary code execution, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.

🟠

Likely Case

Arbitrary code execution within the Chrome sandbox, allowing attacker to escape sandbox and compromise the underlying system.

🟢

If Mitigated

Limited impact if Chrome's sandbox is intact and other security controls prevent renderer compromise, though heap corruption could still cause crashes.

🌐 Internet-Facing: HIGH - Chrome is commonly used to browse untrusted websites, making internet-facing systems highly vulnerable.

🏢 Internal Only: MEDIUM - Internal users may still encounter malicious content via emails or compromised internal sites.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires first compromising the renderer process, then triggering the heap overflow. The bug report suggests this was found through fuzzing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 84.0.4147.125 and later

Vendor Advisory: https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html

Restart Required: Yes

Instructions:

1. Open Chrome. 2. Click the three-dot menu. 3. Go to Help > About Google Chrome. 4. Chrome will automatically check for and install updates. 5. Click Relaunch to restart Chrome with the patched version.

🔧 Temporary Workarounds

Disable JavaScript

all

Prevents execution of malicious JavaScript that could compromise renderer process

chrome://settings/content/javascript

Use Site Isolation

all

Enforces process separation between websites to limit impact of renderer compromise

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

🧯 If You Can't Patch

Restrict Chrome usage to trusted websites only
Implement application whitelisting to prevent unauthorized Chrome execution

🔍 How to Verify

Check if Vulnerable:

Check Chrome version: If version is less than 84.0.4147.125, system is vulnerable.

Check Version:

On Windows/Linux/macOS: Open Chrome and navigate to chrome://version/

Verify Fix Applied:

Confirm Chrome version is 84.0.4147.125 or higher after update.

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports with memory corruption signatures
Unexpected Chrome process termination

Network Indicators:

Unusual outbound connections from Chrome processes
Traffic to known exploit hosting domains

SIEM Query:

source="chrome" AND (event_type="crash" OR memory_corruption="true")

📊 Metadata

CVE ID: CVE-2020-6548

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-787

Published: September 21, 2020

Last Updated: November 21, 2024

🔗 References

https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html Release Notes,Vendor Advisory
https://crbug.com/1103827 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EE7XWIZBME7JAY7N6CGPET4CLNHHEIVT/
https://security.gentoo.org/glsa/202101-30 Third Party Advisory
https://www.debian.org/security/2021/dsa-4824 Third Party Advisory
https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html Release Notes,Vendor Advisory
https://crbug.com/1103827 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EE7XWIZBME7JAY7N6CGPET4CLNHHEIVT/
https://security.gentoo.org/glsa/202101-30 Third Party Advisory
https://www.debian.org/security/2021/dsa-4824 Third Party Advisory

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🔗 Related Vulnerabilities

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