NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
.NET
.NET NuGet
Not in CISA KEV
MEDIUM severity

CVE-2018-7559 — OPCFoundation.NetStandard…

MEDIUMFix: OPCFoundation/UA-.NET-Legacy@e2a781b

CVE-2018-7559 is a medium-severity (CVSS 5.3) CWE-320 vulnerability in OPCFoundation.NetStandard.Opc.Ua. A fix is available for OPCFoundation.NetStandard.Opc.Ua — see the affected versions and patch details below.

OPC UA applications can allow a remote attacker to determine a Server's private key

Also known asGHSA-gr4c-5rq6-cgh3
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk-0.02%
Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk
0.00%0.69%1.39%2.08%0.3%1.1%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
.NETOPCFoundation.NetStandard.Opc.Ua

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

An issue was discovered in OPC UA .NET Standard Stack and Sample Code before GitHub commit 2018-04-12, and OPC UA .NET Legacy Stack and Sample Code before GitHub commit 2018-03-13. A vulnerability in OPC UA applications can allow a remote attacker to determine a Server's private key by sending carefully constructed bad UserIdentityTokens as part of an oracle attack.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetOPCFoundation.NetStandard.Opc.Uaall versions1.3.352.12dotnet add package OPCFoundation.NetStandard.Opc.Ua --version 1.3.352.12

Affected Products

2 products · 2 configurations
Application
ua-.net-legacyopcfoundation
≤ 1.03.342
range
Application
ua-.netstandardopcfoundation
≤ 1.03.352.10
range

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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update OPCFoundation.NetStandard.Opc.Ua to 1.3.352.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-7559 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.

Frequently Asked Questions

An issue was discovered in OPC UA .NET Standard Stack and Sample Code before GitHub commit 2018-04-12, and OPC UA .NET Legacy Stack and Sample Code before GitHub commit 2018-03-13. A vulnerability in OPC UA applications can allow a remote attacker to determine a Server's private key by sending carefully constructed bad UserIdentityTokens as part of an oracle attack.
O3 Security · Impact-Aware SCA

Is CVE-2018-7559 in your dependencies?

Find it across NuGet, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2018-7559: OPCFoundation — Fixed in 1.3.352.12