CVE-2021-21227
📋 TL;DR
This vulnerability in Chrome's V8 JavaScript engine allows remote attackers to potentially execute arbitrary code or cause denial of service through heap corruption. Attackers can exploit this by tricking users into visiting a malicious webpage. All users running vulnerable Chrome versions 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...
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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 code execution within browser sandbox.
If Mitigated
No impact if Chrome is updated to patched version or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Exploitation requires user to visit malicious webpage. No public exploit code known at time of disclosure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 90.0.4430.93 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop_26.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' to restart Chrome with updated version.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript execution in Chrome to block exploitation vectors.
chrome://settings/content/javascript
Use Site Isolation
allEnable site isolation to limit impact of potential exploitation.
chrome://flags/#enable-site-per-process
🧯 If You Can't Patch
- Restrict access to untrusted websites using web filtering/proxy solutions.
- Implement application whitelisting to prevent unauthorized code execution.
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: Open Chrome > Menu > Help > About Google Chrome. If version is below 90.0.4430.93, system is vulnerable.Check Version:
google-chrome --versionVerify Fix Applied:
Confirm Chrome version is 90.0.4430.93 or higher after update.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination logs
- Security event logs showing suspicious browser activity
Network Indicators:
- Requests to known malicious domains hosting exploit code
- Unusual outbound connections from browser processes
SIEM Query:
source="chrome_logs" AND (event="crash" OR event="process_termination") AND version<"90.0.4430.93"🔗 References
- https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop_26.html
- https://crbug.com/1199345
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4911
- https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop_26.html
- https://crbug.com/1199345
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4911
