CVE-2021-47705
CVE-2021-47705 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 4.0 base score 8.7)
- EPSS exploit prediction: 0% (34th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2021-34734
- Weakness: CWE-787
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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 arrays through multiple functions. Attackers can exploit improper boundary validation in CNC_Ctrl.dll to cause heap corruption and potentially gain system-level access.
- How severe is CVE-2021-47705?
- CVE-2021-47705 has a CVSS 4.0 base score of 8.7, rated high severity.
- Is CVE-2021-47705 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2021-47705?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2021-47705 have an EU (EUVD) identifier?
- Yes. CVE-2021-47705 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34734.
- When was CVE-2021-47705 published?
- CVE-2021-47705 was published on 2025-12-09 and last updated on 2026-06-17.
References
- 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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