CVE-2021-30562
📋 TL;DR
This vulnerability is a use-after-free memory corruption flaw in Chrome's WebSerial API that allows attackers to potentially execute arbitrary code or cause denial of service. It affects all users running Chrome versions prior to 91.0.4472.164. Attackers can exploit this by tricking users into visiting a malicious webpage.
💻 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 complete system compromise, data theft, or ransomware deployment.
Likely Case
Browser crash (denial of service) or limited memory corruption leading to information disclosure.
If Mitigated
No impact if Chrome is fully patched or WebSerial API is disabled.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious page) and knowledge of heap manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 91.0.4472.164 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/07/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open Chrome. 2. Click three-dot menu → Help → About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' to restart Chrome with the patched version.
🔧 Temporary Workarounds
Disable WebSerial API
allDisable the vulnerable WebSerial API via Chrome flags
Navigate to chrome://flags/#enable-experimental-web-platform-features
Set to 'Disabled'
Relaunch Chrome
Use Chrome Enterprise policies
allDisable WebSerial via group policy for enterprise deployments
Set SerialAllowAllPortsForUrls policy to empty list
Set SerialAllowUsbDevicesForUrls policy to empty list
🧯 If You Can't Patch
- Use alternative browsers without WebSerial support until patching is possible
- Implement network filtering to block malicious websites and restrict internet browsing
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: if below 91.0.4472.164, system is vulnerableCheck Version:
On Chrome: chrome://version/ or 'google-chrome --version' in terminalVerify Fix Applied:
Confirm Chrome version is 91.0.4472.164 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with WebSerial-related stack traces
- Unexpected Chrome process termination
Network Indicators:
- Requests to suspicious domains with serial API parameters
- Unusual WebSocket or serial port communication
SIEM Query:
source="chrome_logs" AND (event="crash" OR event="exception") AND process="chrome" AND message="*WebSerial*"