CVE-2021-47705 HIGH

CVE-2021-47705: CNC_Ctrl DllUnregisterServer Access Violation

Vendor Commax Co., Ltd.
Product COMMAX UMS Client ActiveX Control
Weakness CWE-787
Published December 9, 2025
Last update April 7, 2026

CVSS base score

8.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction
Confidentiality
Integrity

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

December 9, 2025 CVE published
April 7, 2026 Record updated