CVE-2021-21169
📋 TL;DR
This vulnerability allows a remote attacker to perform out-of-bounds memory access in Chrome's V8 JavaScript engine via a crafted HTML page. Attackers could potentially execute arbitrary code or cause denial of service. All users of affected Chrome versions are vulnerable when visiting malicious websites.
💻 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 fully patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Exploit requires user to visit malicious webpage. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 89.0.4389.72 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/03/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.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by disabling JavaScript execution in Chrome
Use Site Isolation
allEnhances Chrome's site isolation feature to limit impact
🧯 If You Can't Patch
- Block access to untrusted websites using web filtering/proxy
- Use application control to restrict Chrome usage to essential sites only
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in Settings → About Chrome. If version is below 89.0.4389.72, system is vulnerable.Check Version:
google-chrome --versionVerify Fix Applied:
Confirm Chrome version is 89.0.4389.72 or higher in About Chrome page.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination logs
- Security event logs showing exploit attempts
Network Indicators:
- Requests to known malicious domains hosting exploit code
- Unusual outbound connections from Chrome processes
SIEM Query:
source="chrome" AND (event_type="crash" OR process_name="chrome.exe" AND action="terminated")🔗 References
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
- https://crbug.com/1166138
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4886
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
- https://crbug.com/1166138
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/
- https://security.gentoo.org/glsa/202104-08
- https://www.debian.org/security/2021/dsa-4886
