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HIGH severity

GHSA-vpf7-r2fv-75m9 OPCFoundation.NetStandard…

HIGH

GHSA-vpf7-r2fv-75m9 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in OPCFoundation.NetStandard.Opc.Ua.Server. A fix is available for OPCFoundation.NetStandard.Opc.Ua.Server — see the affected versions and patch details below.

Uncontrolled Resource Consumption in OPC UA .NET Standard Reference Server

Also known asCVE-2023-27321
Published
May 5, 2023
Updated
May 8, 2024
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-vpf7-r2fv-75m9.

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-vpf7-r2fv-75m9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
.NETOPCFoundation.NetStandard.Opc.Ua.Server

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

This security update resolves a vulnerability in the OPC UA .NET Standard Reference Server that allows remote attackers to send malicious requests that consume all memory available to the server.

https://files.opcfoundation.org/SecurityBulletins/OPC%20Foundation%20Security%20Bulletin%20CVE-2023-27321.pdf

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetOPCFoundation.NetStandard.Opc.Ua.Serverall versions1.4.371.86dotnet add package OPCFoundation.NetStandard.Opc.Ua.Server --version 1.4.371.86

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for OPCFoundation.NetStandard.Opc.Ua.Server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update OPCFoundation.NetStandard.Opc.Ua.Server to 1.4.371.86 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vpf7-r2fv-75m9 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-vpf7-r2fv-75m9 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-vpf7-r2fv-75m9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

This security update resolves a vulnerability in the OPC UA .NET Standard Reference Server that allows remote attackers to send malicious requests that consume all memory available to the server. https://files.opcfoundation.org/SecurityBulletins/OPC%20Foundation%20Security%20Bulletin%20CVE-2023-27321.pdf
O3 Security · Impact-Aware SCA

Is GHSA-vpf7-r2fv-75m9 in your dependencies?

O3 Security finds GHSA-vpf7-r2fv-75m9 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-vpf7-r2fv-75m9: High 7.5 severity | O3 Security