CVE-2021-21179
📋 TL;DR
This is a use-after-free vulnerability in Chrome's Network Internals component on Linux systems. It allows remote attackers to potentially execute arbitrary code or cause heap corruption by tricking users into visiting a malicious webpage. Only Linux users running Chrome versions before 89.0.4389.72 are affected.
💻 Affected Systems
- Google Chrome
📦 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
Remote code execution leading to full system compromise, data theft, or ransomware deployment.
Likely Case
Browser crash, denial of service, or limited information disclosure from memory corruption.
If Mitigated
No impact if Chrome is updated to patched version or if vulnerable systems are isolated.
🎯 Exploit Status
Requires user to visit malicious webpage but no authentication needed. Use-after-free vulnerabilities often require precise timing and memory manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 89.0.4389.72
Vendor Advisory: https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open Chrome. 2. Click menu (three dots) → Help → About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' when prompted. For Linux package managers: sudo apt update && sudo apt upgrade google-chrome-stable
🔧 Temporary Workarounds
Disable JavaScript
allPrevents execution of malicious JavaScript that could trigger the vulnerability
chrome://settings/content/javascript → Block
Use Chrome Sandbox
linuxEnsure Chrome sandbox is enabled to limit impact if exploited
Check chrome://sandbox/ for sandbox status
🧯 If You Can't Patch
- Restrict web browsing to trusted sites only using browser extensions or proxy policies
- Implement application whitelisting to prevent unauthorized Chrome execution
🔍 How to Verify
Check if Vulnerable:
Open Chrome, go to chrome://version and check if version is less than 89.0.4389.72Check Version:
google-chrome --versionVerify Fix Applied:
Confirm Chrome version is 89.0.4389.72 or higher via chrome://version📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with memory corruption signatures
- Unexpected Chrome process termination
Network Indicators:
- Connections to suspicious domains followed by Chrome crashes
SIEM Query:
source="chrome_logs" AND (event="crash" OR event="segfault") AND version<"89.0.4389.72"🔗 References
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
- https://crbug.com/1174943
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4886
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
- https://crbug.com/1174943
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4886
