CVE-2021-47719
📋 TL;DR
This vulnerability in COMMAX WebViewer ActiveX Control allows attackers to execute arbitrary code by exploiting a buffer overflow through excessively long string arrays. It affects systems using the vulnerable ActiveX control in web applications or documents. Attackers can gain code execution with the privileges of the user running the control.
💻 Affected Systems
- COMMAX WebViewer ActiveX Control
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the user running the vulnerable control, potentially leading to complete system takeover, data theft, or lateral movement.
Likely Case
Arbitrary code execution in the context of the current user, allowing installation of malware, data exfiltration, or system manipulation.
If Mitigated
Limited impact if control is not used, properly sandboxed, or running with minimal privileges.
🎯 Exploit Status
Exploit code is publicly available, making exploitation straightforward for attackers with access to target systems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.commax.com
Restart Required: No
Instructions:
Check vendor website for updates. If patch is available, download and install the latest version of COMMAX WebViewer ActiveX Control.
🔧 Temporary Workarounds
Disable ActiveX Control
windowsPrevent the vulnerable ActiveX control from loading in Internet Explorer
reg add "HKLM\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{CLSID_OF_CONTROL}" /v "Compatibility Flags" /t REG_DWORD /d 0x400 /f
Set Kill Bit
windowsSet kill bit to prevent control from running
reg add "HKLM\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{CLSID_OF_CONTROL}" /v "Compatibility Flags" /t REG_DWORD /d 0x400 /f
🧯 If You Can't Patch
- Remove or disable the vulnerable ActiveX control from all systems
- Implement application whitelisting to prevent execution of unauthorized ActiveX controls
🔍 How to Verify
Check if Vulnerable:
Check if Commax_WebViewer.ocx version 2.1.4.5 or earlier exists on systemCheck Version:
wmic datafile where name="C:\\path\\to\\Commax_WebViewer.ocx" get versionVerify Fix Applied:
Verify the control is no longer present or has been updated to a patched version📡 Detection & Monitoring
Log Indicators:
- Process creation events related to Commax_WebViewer.ocx
- Application crash logs mentioning the control
Network Indicators:
- HTTP requests loading the vulnerable ActiveX control
- Unusual network traffic from systems with the control
SIEM Query:
source="windows" AND (process_name="*Commax*" OR file_name="*Commax_WebViewer.ocx*")