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Vulnerabilities

Vulnerability · CVE-2021-47705

COMMAX UMS Client ActiveX Control 1.7.0.2 contains a heap-based buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string a

Published Dec 9, 2025 · catalog updated Apr 7, 2026 · COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control

Last checked Oct 27, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-47705. EPSS is 0.49%. Act only if a listed version of COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.49%
Remediation
Vendor / distro source
Affected products
vendor COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control 1.7.0.2

COMMAX UMS Client ActiveX Control 1.7.0.2 contains a heap-based buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit improper boundary validation in CNC_Ctrl.dll to cause heap corruption and potentially gain system-level access.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control 1.7.0.21.7.0.2

How to fix CVE-2021-47705

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-47705. EPSS is 0.49%. Act only if a listed version of COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control is installed.

Which versions are affected?

Compare what you have installed with COMMAX Co., Ltd. COMMAX UMS Client ActiveX Control 1.7.0.2 1.7.0.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.49%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 9, 2025 · EUVD

    Detected

    COMMAX UMS Client ActiveX Control 1.7.0.2 contains a heap-based buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit improper boundary validation in CNC_Ctrl.dll to cause heap corruption and potentially gain system-level access.

  2. Apr 7, 2026 · EUVD

    Updated

    COMMAX UMS Client ActiveX Control 1.7.0.2 contains a heap-based buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit improper boundary validation in CNC_Ctrl.dll to cause heap corruption and potentially gain system-level access.

Sources

  • CVE.orgVulnerability recordCVE-2021-47705

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-47705

    30-day exploitation probability 0.49%

    first.org
  • EUVDVulnerability recordEUVD-2021-34734

    COMMAX UMS Client ActiveX Control 1.7.0.2 contains a heap-based buffer overflow vulnerability that allows attackers to execute arbitrary code by providing excessively long string arrays through multiple functions. Attackers can exploit improper boundary validation in CNC_Ctrl.dll

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 27, 2026
  • FIRST EPSSOct 26, 2026
  • EUVDOct 26, 2026