CVE-2021-37975
📋 TL;DR
This is a use-after-free vulnerability in Chrome's V8 JavaScript engine that allows remote attackers to potentially exploit heap corruption. Attackers can trigger this vulnerability by tricking users into visiting a malicious HTML page. All users running vulnerable versions of Google Chrome 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
Full remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Arbitrary code execution within the Chrome sandbox, potentially leading to data theft, credential harvesting, or further exploitation.
If Mitigated
Limited impact due to Chrome's sandboxing, but still potential for data exfiltration or privilege escalation.
🎯 Exploit Status
Proof of concept available on Packet Storm. Exploitation requires user interaction (visiting malicious page).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 94.0.4606.71 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop_30.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
allTemporarily disable JavaScript execution in Chrome to prevent exploitation
chrome://settings/content/javascript → Block
Use Site Isolation
allEnsure site isolation is enabled for additional protection
chrome://flags/#site-isolation-trial-opt-out → Disabled
🧯 If You Can't Patch
- Use alternative browsers until Chrome can be updated
- Implement network filtering to block malicious websites
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in About Google Chrome pageCheck Version:
google-chrome --versionVerify Fix Applied:
Verify Chrome version is 94.0.4606.71 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination
- Memory access violation logs
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 message="access violation")🔗 References
- http://packetstormsecurity.com/files/172847/Chrome-V8-Logic-Bug-Use-After-Free.html
- https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop_30.html
- https://crbug.com/1252918
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D63JZ3ROXCUHP4CFWDHCPZNTGET7T34R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRFXUDH46PFVE75VQVWY6PYY5DK3S2XT/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNARCF5HEZK7GJXZRN5TQ45AQDCRM2WO/
- https://www.debian.org/security/2022/dsa-5046
- http://packetstormsecurity.com/files/172847/Chrome-V8-Logic-Bug-Use-After-Free.html
- https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop_30.html
- https://crbug.com/1252918
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D63JZ3ROXCUHP4CFWDHCPZNTGET7T34R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRFXUDH46PFVE75VQVWY6PYY5DK3S2XT/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNARCF5HEZK7GJXZRN5TQ45AQDCRM2WO/
- https://www.debian.org/security/2022/dsa-5046
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-37975
