CVE-2026-50196 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in Steeltoe.Discovery.Eureka. O3 Security confirms whether CVE-2026-50196 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Steeltoe.Discovery.Eureka: Unrecognized DataCenterInfo.Name poisons entire registry fetch
Real-World Exposure
Steeltoe.Discovery.Eureka.NETSteeltoe.Discovery.EurekaReal-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
Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. In Steeltoe.Discovery.Eureka prior to versions 4.2.0 and 3.4.0, DataCenterInfo.FromJson throws ArgumentException for any name value other than "MyOwn" or "Amazon", despite the Java Eureka specification defining a third valid value: "Netflix". The exception propagates through the entire registry deserialization chain and is swallowed by the periodic cache refresh task, leaving the local service registry permanently empty or stale. Versions 4.2.0 and 3.4.0 patch the issue. If an immediate upgrade is not possible, remove any registrations using unsupported DataCenterInfo.name values from the registry. In mixed Java/Spring and Steeltoe environments, audit for the Netflix data center type before deploying Steeltoe Eureka clients.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Steeltoe.Discovery.Eureka | ≥ 4.0.0&&< 4.2.0 | 4.2.0 |
| .NETNuGet | Steeltoe.Discovery.Eureka | all versions | 3.4.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Steeltoe.Discovery.Eureka. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Steeltoe.Discovery.Eureka to 4.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50196 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether CVE-2026-50196 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-50196. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-50196 in your dependencies?
O3 detects CVE-2026-50196 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.