CVE-2021-37991
📋 TL;DR
This vulnerability is a race condition in Chrome's V8 JavaScript engine that could allow a remote attacker to trigger heap corruption by tricking users into visiting a malicious HTML page. It affects all Chrome users prior to version 95.0.4638.54, potentially leading to arbitrary code execution.
💻 Affected Systems
- Google Chrome
- Chromium-based browsers
- Debian packages containing Chromium
📦 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 with the same privileges as the Chrome process, potentially leading to full system compromise, data theft, or malware installation.
Likely Case
Browser crash or instability, with potential for limited code execution in the browser sandbox.
If Mitigated
No impact if Chrome is fully patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Race conditions are difficult to exploit reliably, requiring precise timing. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 95.0.4638.54 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html
Restart Required: Yes
Instructions:
1. Open Chrome and click the three-dot menu. 2. Go to Help > About Google Chrome. 3. Chrome will automatically check for updates and install version 95.0.4638.54 or later. 4. Click 'Relaunch' to restart Chrome with the fix.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents execution of the malicious JavaScript that triggers the race condition.
chrome://settings/content/javascript > Block
Use Site Isolation
allEnhances Chrome's site isolation feature to limit impact if exploited.
chrome://flags/#enable-site-per-process > Enable
🧯 If You Can't Patch
- Use alternative browsers until Chrome can be updated
- Implement network filtering to block known malicious sites and restrict web browsing
🔍 How to Verify
Check if Vulnerable:
Check Chrome version via chrome://version and compare to 95.0.4638.54Check Version:
chrome://version or 'google-chrome --version' on LinuxVerify Fix Applied:
Confirm Chrome version is 95.0.4638.54 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination logs
- Sandbox escape attempts
Network Indicators:
- Requests to suspicious domains hosting HTML/JS content
- Unusual outbound connections from Chrome processes
SIEM Query:
process_name:"chrome.exe" AND (event_id:1000 OR event_id:1001) OR http_user_agent:"Chrome/9[0-4]."🔗 References
- https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html
- https://crbug.com/1250660
- https://www.debian.org/security/2022/dsa-5046
- https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html
- https://crbug.com/1250660
- https://www.debian.org/security/2022/dsa-5046
