CVE-2021-37985
📋 TL;DR
This is a use-after-free vulnerability in Chrome's V8 JavaScript engine that allows remote attackers to potentially exploit heap corruption. Attackers can trigger this by convincing users to connect to a debugger and visit a malicious HTML page. All Chrome users prior to version 95.0.4638.54 are affected.
💻 Affected Systems
- Google Chrome
- Chromium-based browsers
📦 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 ransomware deployment
Likely Case
Browser crash or sandbox escape allowing limited code execution within browser context
If Mitigated
No impact if Chrome is fully patched or debugger connections are blocked
🎯 Exploit Status
Requires user interaction (allowing debugger connection) but no authentication needed
🛠️ 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 menu > Help > About Google Chrome 2. Chrome will automatically check for and install updates 3. Click 'Relaunch' to restart Chrome with the update
🔧 Temporary Workarounds
Disable remote debugging
allPrevent Chrome from accepting remote debugger connections
chrome://flags/#enable-devtools-experiments -> Disabled
chrome://flags/#debug-packed-apps -> Disabled
Use Chrome sandboxing
allEnsure Chrome sandbox is enabled to limit potential impact
chrome://flags/#enable-site-per-process -> Enabled
🧯 If You Can't Patch
- Block access to untrusted websites and restrict browser usage to essential sites only
- Implement application whitelisting to prevent execution of unknown binaries from browser context
🔍 How to Verify
Check if Vulnerable:
Check Chrome version via chrome://settings/help or 'chrome://version/'Check Version:
On Windows: "C:\Program Files\Google\Chrome\Application\chrome.exe" --version
On Linux: google-chrome --version
On macOS: /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --versionVerify Fix Applied:
Confirm Chrome version is 95.0.4638.54 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with V8-related stack traces
- Unexpected debugger connection attempts in Chrome logs
Network Indicators:
- Unusual outbound connections from Chrome process after visiting websites
- Traffic to known malicious domains hosting exploit code
SIEM Query:
source="chrome_logs" AND ("V8" OR "debugger" OR "heap corruption") AND severity=ERROR🔗 References
- https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html
- https://crbug.com/1241860
- https://www.debian.org/security/2022/dsa-5046
- https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html
- https://crbug.com/1241860
- https://www.debian.org/security/2022/dsa-5046
