CVE-2021-4078
📋 TL;DR
This vulnerability is a type confusion flaw in Chrome's V8 JavaScript engine that allows a remote attacker to potentially exploit heap corruption. Attackers could execute arbitrary code or cause denial of service by tricking users into visiting a malicious webpage. All users of affected Chrome versions are vulnerable.
💻 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 or limited code execution within the sandboxed browser process.
If Mitigated
No impact if Chrome is updated to patched version or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Type confusion vulnerabilities in V8 are commonly exploited in the wild. The bug report suggests active exploitation was possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 96.0.4664.93
Vendor Advisory: https://chromereleases.googleblog.com/2021/12/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 update.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by disabling JavaScript execution in Chrome
chrome://settings/content/javascript → Block
Use Site Isolation
allEnables site isolation to limit impact of renderer process compromise
chrome://flags/#enable-site-per-process → Enable
🧯 If You Can't Patch
- Block access to untrusted websites using web filtering or proxy rules
- Deploy application control to prevent execution of malicious payloads
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in About Google Chrome page. If version is below 96.0.4664.93, system is vulnerable.Check Version:
google-chrome --version (Linux) or "C:\Program Files\Google\Chrome\Application\chrome.exe" --version (Windows)Verify Fix Applied:
Confirm Chrome version is 96.0.4664.93 or higher in About Google Chrome page.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Renderer process termination events
- Unexpected memory access violations
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 memory_violation)🔗 References
- https://chromereleases.googleblog.com/2021/12/stable-channel-update-for-desktop.html
- https://crbug.com/1268738
- https://security.gentoo.org/glsa/202208-25
- https://www.debian.org/security/2022/dsa-5046
- https://chromereleases.googleblog.com/2021/12/stable-channel-update-for-desktop.html
- https://crbug.com/1268738
- https://security.gentoo.org/glsa/202208-25
- https://www.debian.org/security/2022/dsa-5046
