Read the docs
TI-2023-12056 Aliases CVE-2023-27321GHSA-vpf7-r2fv-75m9

Uncontrolled resource consumption in OPC Foundation UA .NET Standard

Priority MEDIUM 41CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-400.

Summary

OPC Foundation UA .NET Standard ConditionRefresh Resource Exhaustion Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of OPC Foundation UA .NET Standard. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of OPC UA ConditionRefresh requests. By sending a large number of requests, an attacker can consume all available resources on the server. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-20505.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01047 64th percentileScored 2026-11-07
Fix Fixed OPCFoundation.NetStandard.Opc.Ua.Server (NuGet): 1.4.371.86

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
OPC FoundationUA .NET Standard1.4.371.60—No fix listedCNA
—OPCFoundation.NetStandard.Opc.Ua.Server (NuGet)before 1.4.371.861.4.371.86Patch availableGHSA-vpf7-r2fv-75m9
  • UA .NET Standard VendorOPC Foundation Affected 1.4.371.60 Fixed in — No fix listed CNA
  • OPCFoundation.NetStandard.Opc.Ua.Server (NuGet) Vendor— Affected before 1.4.371.86 Fixed in 1.4.371.86 Patch available GHSA-vpf7-r2fv-75m9

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:opcfoundation:ua-.netstandard:*:*:*:*:*:*:*:*before 1.4.371.86VulnerableOPC Foundation
  • cpe:2.3:a:opcfoundation:ua-.netstandard:*:*:*:*:*:*:*:* Versions before 1.4.371.86 Vulnerable ·OPC Foundation

Remediation

  • Fix · GHSA-vpf7-r2fv-75m9 OPCFoundation.NetStandard.Opc.Ua.Server (NuGet) Fixed in 1.4.371.86 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-27321
  2. 2026-10-03 Alias added: GHSA-vpf7-r2fv-75m9

References

Advisory 3

Other 3

  • TI-2019-13805 In OPC Foundation OPC UA .NET Standard codebase 1.4.357.28, servers do not create… CVSS 3.1HIGH 7.4
  • TI-2023-14784 The OPC UA .NET Standard Reference Server before 1.4.371.86. CVSS 3.1MEDIUM 5.3
  • TI-2018-05465 An issue was discovered in OPC UA .NET Standard Stack and Sample Code before GitHub… CVSS 3.0MEDIUM 5.3
  • TI-2018-08667 Failure to validate certificates in OPC Foundation UA Client Applications communicating… CVSS 3.0MEDIUM 5.3
  • TI-2020-17691 A Privilege Elevation vulnerability in OPC UA .NET Standard Stack 1.4.363.107 could allow… CVSS 3.1MEDIUM 4.4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences