How severe is CVE-2021-40871?

CVE-2021-40871 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-40871 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40871?

CVE-2021-40871 primarily affects Softing Datafeed Opc Suite. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-40871?

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.

When was CVE-2021-40871 published?

CVE-2021-40871 was published on 2021-11-10 and last updated on 2026-06-17.

CVE-2021-40871

CVE-2021-40871 is a high-severity vulnerability in Softing Datafeed Opc Suite with a CVSS 3.x base score of 7.5. 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-843.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-843
Affected product: Softing Datafeed Opc Suite
Published: 2021-11-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-40871?: 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.
How severe is CVE-2021-40871?: CVE-2021-40871 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-40871 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40871?: CVE-2021-40871 primarily affects Softing Datafeed Opc Suite. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-40871?: 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.
When was CVE-2021-40871 published?: CVE-2021-40871 was published on 2021-11-10 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:softing:datafeed_opc_suite:*:*:*:*:*:*:*:*
cpe:2.3:a:softing:opc:*:*:*:*:*:*:*:*
cpe:2.3:a:softing:secure_integration_server:*:*:*:*:*:*:*:*
cpe:2.3:a:softing:th_scope:*:*:*:*:*:*:*:*

More vulnerabilities in Softing Datafeed Opc Suite

CVE-2021-42577 — High (CVSS 7.5): An issue was discovered in Softing OPC UA C++ SDK before 5.70. A malformed OPC/UA message abort packet makes the client…
CVE-2021-40873 — High (CVSS 7.5): An issue was discovered in Softing Industrial Automation OPC UA C++ SDK before 5.66, and uaToolkit Embedded before…
CVE-2021-42262 — Medium (CVSS 6.5): An issue was discovered in Softing OPC UA C++ SDK before 5.70. An invalid XML element in the type dictionary makes the…

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Other CWE-843 vulnerabilities

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CVE-2023-22579 — Critical (CVSS 9.9): Due to improper parameter filtering in the sequalize js library, can a attacker peform injection.
CVE-2026-13776 — Critical (CVSS 9.8): Type Confusion in Dawn in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
CVE-2026-43038 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in…
CVE-2025-70023 — Critical (CVSS 9.8): An issue pertaining to CWE-843: Access of Resource Using Incompatible Type was discovered in transloadit uppy v0.25.6.

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