8.7
HIGH CVSS 4.0
CVE-2021-47719
CNC_Ctrl DllUnregisterServer f5501 Access Violation
Description

COMMAX WebViewer ActiveX Control 2.1.4.5 contains a buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit boundary errors in Commax_WebViewer.ocx to cause buffer overflow conditions and potentially gain code execution.

INFO

Published Date :

Dec. 9, 2025, 9:15 p.m.

Last Modified :

Dec. 9, 2025, 9:15 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2021-47719 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 HIGH [email protected]
Solution
Update ActiveX control to a version that addresses buffer overflow vulnerabilities.
  • Update COMMAX WebViewer ActiveX Control.
  • Apply vendor-provided patches or security updates.
  • Remove or disable vulnerable ActiveX control if possible.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-47719.

URL Resource
https://www.commax.com
https://www.exploit-db.com/exploits/50231
https://www.vulncheck.com/advisories/cncctrl-dllunregisterserver-f-access-violation
https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5663.php
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-47719 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-47719 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-47719 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-47719 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Dec. 09, 2025

    Action Type Old Value New Value
    Added Description COMMAX WebViewer ActiveX Control 2.1.4.5 contains a buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit boundary errors in Commax_WebViewer.ocx to cause buffer overflow conditions and potentially gain code execution.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-787
    Added Reference https://www.commax.com
    Added Reference https://www.exploit-db.com/exploits/50231
    Added Reference https://www.vulncheck.com/advisories/cncctrl-dllunregisterserver-f-access-violation
    Added Reference https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5663.php
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.7
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
VS Confidentiality
VS Integrity
VS Availability
SS Confidentiality
SS Integrity
SS Availability