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Vulnerability record · CVE-2021-47705 · published 9 December 2025

CVE-2021-47705: Out-of-bounds write vulnerability

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.

8.7 CVSS 4.0 High EPSS 0.49% · top 60.6% CWE-787 · Out-of-bounds write Deferred
8.7CVSS 4.0 base score
0.49%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:4.0/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:

References

LinkTags
https://www.commax.com
https://www.exploit-db.com/exploits/50232
https://www.vulncheck.com/advisories/commax-ums-client-activex-control-cnc-ctrl-dll-heap-buffer-overflow
https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5664.php

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Source: NIST National Vulnerability Database (record CVE-2021-47705), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.