What is CVE-2026-81516?

CVE-2026-81516 is a high-severity security vulnerability in Steeltoe.Discovery.Consul (nuget), affecting versions >= 4.0.0, <= 4.2.0. It is fixed in 4.3.0.

How severe is CVE-2026-81516?

CVE-2026-81516 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of Steeltoe.Discovery.Consul are affected by CVE-2026-81516?

Steeltoe.Discovery.Consul (nuget) versions >= 4.0.0, <= 4.2.0 is affected.

Is there a fix for CVE-2026-81516?

Yes. CVE-2026-81516 is fixed in 4.3.0. Upgrade to this version or later.

Is CVE-2026-81516 exploitable, and should I be worried?

Whether CVE-2026-81516 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-81516 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-81516 in Steeltoe.Discovery.Consul

Q: How severe is CVE-2026-81516?

CVE-2026-81516 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of Steeltoe.Discovery.Consul are affected by CVE-2026-81516?

Steeltoe.Discovery.Consul (nuget) versions >= 4.0.0, <= 4.2.0 is affected.

Q: Is there a fix for CVE-2026-81516?

Yes. CVE-2026-81516 is fixed in 4.3.0. Upgrade to this version or later.

Q: Is CVE-2026-81516 exploitable, and should I be worried?

Whether CVE-2026-81516 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-81516 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-81516?

Upgrade Steeltoe.Discovery.Consul to 4.3.0 or later.

Summary

Steeltoe.Discovery.Consul: malformed 'secure' metadata aborts service instance lookup (DoS)

Steeltoe's Consul discovery client parses the secure metadata field on each registered service instance using bool.Parse, which throws on any value other than true or false. A single service instance registered with a malformed secure value (for example yes or 1) aborts construction of the entire instance list for that service, making the service undiscoverable. When GetAllInstancesAsync is used, one malformed instance in any service can abort enumeration across all services.
This is the same "one malformed field aborts the whole batch" availability class as CVE-2026-50196, but affecting the Consul discovery client.

Affected configuration

Application uses ConsulDiscoveryClient (any deployment).
The Consul catalog contains at least one service instance with a secure metadata value that is not true or false.
Mixed-platform environments where non-.NET clients register services with non-standard metadata values are more likely to encounter this condition.

Mitigations

If an immediate upgrade is not possible:

Audit the Consul catalog for service registrations with non-standard secure metadata values.
Restrict write access to the Consul service registration API to trusted services.

Impact

Any principal that can register a service in the Consul catalog can trigger a service-discovery outage for all Steeltoe applications resolving that service. The outage affects all instances of the targeted service, not just the malformed one, and persists until the offending registration is removed.

CVE-2026-81516 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.3.0); upgrading removes the vulnerable code path.

Affected versions

Steeltoe.Discovery.Consul (>= 4.0.0, <= 4.2.0)

Security releases

Steeltoe.Discovery.Consul → 4.3.0 (nuget)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade Steeltoe.Discovery.Consul to 4.3.0 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-81516? CVE-2026-81516 is a high-severity security vulnerability in Steeltoe.Discovery.Consul (nuget), affecting versions >= 4.0.0, <= 4.2.0. It is fixed in 4.3.0.
How severe is CVE-2026-81516? CVE-2026-81516 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of Steeltoe.Discovery.Consul are affected by CVE-2026-81516? Steeltoe.Discovery.Consul (nuget) versions >= 4.0.0, <= 4.2.0 is affected.
Is there a fix for CVE-2026-81516? Yes. CVE-2026-81516 is fixed in 4.3.0. Upgrade to this version or later.
Is CVE-2026-81516 exploitable, and should I be worried? Whether CVE-2026-81516 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-81516 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-81516? Upgrade Steeltoe.Discovery.Consul to 4.3.0 or later.