Vulnerabilities in pkg:nuget/Steeltoe.Discovery.Eureka

PACKAGE
Advisory Identifier: GHSA-hr73-3gpv-hh6q
Advisory Summary

CVE-2026-81515 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-755: Improper Handling of Exceptional Conditions) affecting Steeltoe.Discovery.Eureka libraries in the NuGet ecosystem. The issue involves malformed enum/bool/timestamp field aborts entire registry fetch (dos). Remediation is available by upgrading affected packages to version 4.3.0.

3 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:nuget/Steeltoe.Discovery.Eureka

3 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:nuget/Steeltoe.Discovery.Eureka. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-hr73-3gpv-hh6q CVE-2026-81515 HIGH Steeltoe.Discovery.Eureka: malformed enum/bool/timestamp field aborts entire registry fetch (DoS)
GHSA-j8ph-6fxj-g533 CVE-2026-50196 HIGH Steeltoe.Discovery.Eureka: Unrecognized DataCenterInfo.Name poisons entire registry fetch
GHSA-vmcp-66r5-3pcp CVE-2024-40636 LOW Steeltoe Leaks Basic Auth Credentials to Logs After Fetch Registry Error

CVE-2026-81515 at a Glance

CVE Identifier CVE-2026-81515
GHSA Identifier GHSA-hr73-3gpv-hh6q
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-755: Improper Handling of Exceptional Conditions
Affected Product Steeltoe.Discovery.Eureka
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-81515

To remediate this vulnerability, upgrade all affected Steeltoe.Discovery.Eureka dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Steeltoe.Discovery.Eureka fixed: 4.3.0
Upgrade Steeltoe.Discovery.Eureka to 4.3.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for Steeltoe.Discovery.Eureka

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-81515, inspect your project dependencies for Steeltoe.Discovery.Eureka:

inspect dependencies for Steeltoe.Discovery.Eureka

Analyze the terminal output to locate any version of Steeltoe.Discovery.Eureka in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.3.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-755: Improper Handling of Exceptional Conditions, where the product does not handle or incorrectly handles an exceptional condition. In Steeltoe.Discovery.Eureka, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary Steeltoe's Eureka discovery client deserializes the registry response as a single unit. If any registered instance contains a field value that cannot be parsed (for example, an unrecognized `actionType`, a non-boolean value for `isCoordinatingDiscoveryServer`, or a non-numeric timestamp), deserialization of the entire registry fails. All Steeltoe Eureka clients connected to that registry then receive an empty or stale instance list until the malformed registration is removed. This is a related but distinct issue from [CVE-2026-50196](https://github.com/advisories/GHSA-j8ph-6fxj-g533), which addressed only the `DataCenterInfo.name` field. ## Impact Any principal that can register or update a service instance in the Eureka registry can trigger a service-discovery outage for all Steeltoe applications connected to the same registry. The outage persists until the offending registration is removed. ## Affected configuration * Application uses `EurekaDiscoveryClient` (any deployment, including self-hosted Eureka). * The registry contains at least one service instance with an unrecognized value in a field such as `actionType`, `status`, `isCoordinatingDiscoveryServer`, or timestamp fields. * Mixed-platform environments — for example, Java or Spring services co-existing in the same Eureka registry — are more likely to encounter this condition. ## Mitigations If an immediate upgrade is not possible: * Audit the Eureka registry for registrations containing non-standard field values, particularly those originating from non-.NET clients. * Restrict write access to the Eureka registration API to trusted services.

CVE-2026-81515 Affected Steeltoe.Discovery.Eureka Versions

1 component(s)
Fixed Versions:
4.3.0
Product / Package Ecosystem Affected Versions Fixed Version
Steeltoe.Discovery.Eureka
NuGet
≥ 4.0.0
< 4.3.0
4.3.0

References

Frequently Asked Questions

What is CVE-2026-81515?
CVE-2026-81515 is a security vulnerability in Steeltoe.Discovery.Eureka involving malformed enum/bool/timestamp field aborts entire registry fetch (DoS) under CWE-755: Improper Handling of Exceptional Conditions.
Which Steeltoe.Discovery.Eureka versions are affected?
Affected versions include releases prior to 4.3.0 across affected packages: Steeltoe.Discovery.Eureka.
What version fixes CVE-2026-81515?
Upgrading to 4.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is Steeltoe.Discovery.Eureka affected?
Yes, Steeltoe.Discovery.Eureka is affected in releases prior to 4.3.0. Upgrade your dependency to 4.3.0 or later.
What is the CVSS score of CVE-2026-81515?
CVE-2026-81515 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-81515?
CVE-2026-81515 is classified under CWE-755: Improper Handling of Exceptional Conditions (The product does not handle or incorrectly handles an exceptional condition.).
How can I check NuGet dependencies for CVE-2026-81515?
Run the dependency tree command: 'inspect dependencies for Steeltoe.Discovery.Eureka'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hr73-3gpv-hh6q",
  "modified" : "2026-09-17T20:30:46Z",
  "published" : "2026-09-17T20:30:45Z",
  "aliases" : [ "CVE-2026-81515" ],
  "summary" : "Steeltoe.Discovery.Eureka: malformed enum/bool/timestamp field aborts entire registry fetch (DoS)",
  "details" : "## Summary\n\nSteeltoe's Eureka discovery client deserializes the registry response as a single unit. If any registered instance contains a field value that cannot be parsed (for example, an unrecognized `actionType`, a non-boolean value for `isCoordinatingDiscoveryServer`, or a non-numeric timestamp), deserialization of the entire registry fails. All Steeltoe Eureka clients connected to that registry then receive an empty or stale instance list until the malformed registration is removed.\n\nThis is a related but distinct issue from [CVE-2026-50196](https://github.com/advisories/GHSA-j8ph-6fxj-g533), which addressed only the `DataCenterInfo.name` field.\n\n## Impact\n\nAny principal that can register or update a service instance in the Eureka registry can trigger a service-discovery outage for all Steeltoe applications connected to the same registry. The outage persists until the offending registration is removed.\n\n## Affected configuration\n\n* Application uses `EurekaDiscoveryClient` (any deployment, including self-hosted Eureka).\n* The registry contains at least one service instance with an unrecognized value in a field such as `actionType`, `status`, `isCoordinatingDiscoveryServer`, or timestamp fields.\n* Mixed-platform environments — for example, Java or Spring services co-existing in the same Eureka registry — are more likely to encounter this condition.\n\n## Mitigations\n\nIf an immediate upgrade is not possible:\n\n* Audit the Eureka registry for registrations containing non-standard field values, particularly those originating from non-.NET clients.\n* Restrict write access to the Eureka registration API to trusted services.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "Steeltoe.Discovery.Eureka"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.3.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.2.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-hr73-3gpv-hh6q"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-81515"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SteeltoeOSS/Steeltoe/commit/bc1c3763aacc1fee82ef9932f338ec08dcb00432"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SteeltoeOSS/Steeltoe/releases/tag/4.3.0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/SteeltoeOSS/security-advisories"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-j8ph-6fxj-g533"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-755" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-17T20:30:45Z",
    "nvd_published_at" : "2026-09-17T16:17:46Z"
  }
}