CVE-2021-21230
📋 TL;DR
This is a type confusion vulnerability in Chrome's V8 JavaScript engine that could allow a remote attacker to execute arbitrary code or cause heap corruption by tricking a user into visiting a malicious webpage. It affects all users running Chrome versions before 90.0.4430.93. The vulnerability requires user interaction but can lead to full system compromise.
💻 Affected Systems
- Google Chrome
- Chromium-based browsers
- Microsoft Edge (Chromium-based)
- Brave Browser
- Opera
📦 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 complete system compromise, data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Browser crash (denial of service) or limited code execution within the browser sandbox, potentially stealing session cookies or credentials.
If Mitigated
No impact if Chrome is fully patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Exploitation requires user to visit a malicious webpage. The bug report (crbug.com/1198705) contains technical details that could aid exploit development.
🛠️ 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 the 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 JavaScript
allPrevents exploitation by disabling JavaScript execution in Chrome
chrome://settings/content/javascript → Block
Use Site Isolation
allEnhances sandboxing to limit impact of successful exploitation
chrome://flags/#enable-site-per-process → Enable
🧯 If You Can't Patch
- Use alternative browsers that are not Chromium-based
- Implement network filtering to block malicious websites and restrict internet access
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: If version is below 90.0.4430.93, the system is vulnerable.Check Version:
google-chrome --version (Linux) or chrome://version (all platforms)Verify Fix Applied:
Confirm Chrome version is 90.0.4430.93 or higher after update.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination
- Memory access violation errors
Network Indicators:
- Connections to suspicious domains hosting malicious HTML/JavaScript
- Unusual outbound traffic from Chrome processes
SIEM Query:
source="chrome" AND (event_type="crash" OR message="*V8*" OR message="*heap*corruption*")🔗 References
- https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop_26.html
- https://crbug.com/1198705
- 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/1198705
- 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
