CVE-2021-30610
📋 TL;DR
This vulnerability is a use-after-free flaw in Chromium's Extensions API that allows remote attackers to execute arbitrary code or cause a denial of service via a crafted HTML page. It affects all Chromium-based browsers including Google Chrome, Microsoft Edge, and other derivatives. Users who haven't updated their browsers are vulnerable to exploitation.
💻 Affected Systems
- Google Chrome
- Microsoft Edge
- Chromium
- Other Chromium-based browsers
📦 What is this software?
Edge by Microsoft
Edge Chromium by Microsoft
Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the same privileges as the browser process, potentially leading to full system compromise if the browser runs with elevated privileges.
Likely Case
Browser crash (denial of service) or limited code execution within browser sandbox boundaries.
If Mitigated
No impact if browser is fully patched or if vulnerable extensions are disabled.
🎯 Exploit Status
Use-after-free vulnerabilities in browser engines are commonly exploited in the wild. The Extensions API attack surface is well-understood by attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Chrome 93.0.4577.82 and later, Edge 93.0.961.47 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open browser settings 2. Navigate to 'About Chrome/Edge' 3. Allow browser to check for and install updates 4. Restart browser when prompted
🔧 Temporary Workarounds
Disable browser extensions
allTemporarily disable all browser extensions to reduce attack surface while awaiting patch
chrome://extensions/ -> toggle off all extensions
edge://extensions/ -> toggle off all extensions
Enable site isolation
allEnsure site isolation is enabled to limit impact of potential exploitation
chrome://flags/#site-isolation-trial-opt-out -> set to 'Disabled'
edge://flags/#site-isolation-trial-opt-out -> set to 'Disabled'
🧯 If You Can't Patch
- Use alternative non-Chromium browsers until patches can be applied
- Implement network filtering to block known malicious sites and restrict browser usage to trusted domains only
🔍 How to Verify
Check if Vulnerable:
Check browser version in settings -> About Chrome/Edge. If version is below 93.0.4577.82 for Chrome or 93.0.961.47 for Edge, you are vulnerable.Check Version:
chrome://version/ or edge://version/ in browser address barVerify Fix Applied:
Confirm browser version is 93.0.4577.82 or higher for Chrome, 93.0.961.47 or higher for Edge.📡 Detection & Monitoring
Log Indicators:
- Browser crash reports with memory access violations
- Unexpected extension process terminations
- Suspicious extension API calls in browser logs
Network Indicators:
- Connections to known malicious domains serving exploit code
- Unusual outbound connections from browser processes
SIEM Query:
source="browser_logs" AND (event="crash" OR event="access_violation") AND process="chrome.exe" OR process="msedge.exe"🔗 References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IPJPUSAWIJMQFBQQQYXAICLI4EKFQOH6/
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-30610
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IPJPUSAWIJMQFBQQQYXAICLI4EKFQOH6/
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-30610
