HOMEVULNERABILITIESCVE-2021-40871
HIGH

CVE-2021-40871

CWE-843Published: November 10, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

An issue was discovered in Softing Industrial Automation OPC UA C++ SDK before 5.66. Remote attackers to cause a denial of service (DoS) by sending crafted messages to a OPC/UA client. The client process may crash unexpectedly because of a wrong type cast, and must be restarted.

NVD Source

Technical Analysis

CVE-2021-40871 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

softing4 product(s)
datafeed opc suiteopcsecure integration serverth scope
Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://industrial.softing.com/
ADVISORYhttps://industrial.softing.com/fileadmin/sof-files/pdf/ia/support/Security_Bulletin-CVE-2021-40871.pdf
ADVISORYhttps://industrial.softing.com/
ADVISORYhttps://industrial.softing.com/fileadmin/sof-files/pdf/ia/support/Security_Bulletin-CVE-2021-40871.pdf

All References (4)

→
https://industrial.softing.com/Vendor Advisory
→
https://industrial.softing.com/fileadmin/sof-files/pdf/ia/support/Security_Bulletin-CVE-2021-40871.pdfVendor Advisory
→
https://industrial.softing.com/Vendor Advisory
→
https://industrial.softing.com/fileadmin/sof-files/pdf/ia/support/Security_Bulletin-CVE-2021-40871.pdfVendor Advisory

Quick Facts

CVE IDCVE-2021-40871
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-843
CISA KEVNo
Affected1 vendor(s)
PublishedNov 10, 2021

Related CVEs (CWE-843)

CVE-2010-2299
10.0
CVE-2021-33970
10.0
CVE-2019-20587
9.8
CVE-2024-34392
9.8
CVE-2026-40446
9.8
CVE-2024-8385
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-40871 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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