CVE-2021-47719Public exploitNetwork attack vector

Code execution via oversized ActiveX string arrays

Published Dec 9, 2025 · Updated Apr 7, 2026

Buffer overflow in COMMAX WebViewer ActiveX Control 2.1.4.5 allows attackers to execute arbitrary code through crafted string arrays. Commax_WebViewer.ocx fails to enforce input boundaries when exposed functions process oversized byte-string arrays, leading to an invalid-pointer write inside Internet Explorer. A victim must load the 32-bit ActiveX control in Internet Explorer; successful exploitation runs code in that user's security context and can also crash the browser.

CVSS severity8.7
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in COMMAX WebViewer ActiveX Control 2.1.4.5 allows attackers to execute arbitrary code through crafted string arrays. Commax_WebViewer.ocx fails to enforce input boundaries when exposed functions process oversized byte-string arrays, leading to an invalid-pointer write inside Internet Explorer. A victim must load the 32-bit ActiveX control in Internet Explorer; successful exploitation runs code in that user's security context and can also crash the browser.

The record

CVE
CVE-2021-47719
Published
Dec 9, 2025
Updated
Apr 7, 2026
Vendor
COMMAX
Product
COMMAX WebViewer ActiveX Control
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.1.4.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

COMMAX · COMMAX WebViewer ActiveX Controlversion=2.1.4.5

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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