CVE-2026-81515

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. From 4.0.0 until 4.3.0, EurekaDiscoveryClient deserializes the registry response as one unit, and an unrecognized actionType or status, a non-Boolean isCoordinatingDiscoveryServer, or a nonnumeric timestamp can abort the entire response. A principal that can register or update an instance can cause all connected Steeltoe clients to receive an empty or stale instance list until the malformed registration is removed. The JsonInstanceInfoConverter, BoolStringJsonConverter, and LongStringJsonConverter parsing paths are affected. This issue is distinct from the earlier DataCenterInfo.name parsing vulnerability. This issue is fixed in version 4.3.0.

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. From 4.0.0 until 4.3.0, EurekaDiscoveryClient deserializes the registry response as one unit, and an unrecognized actionType or status, a non-Boolean isCoordinatingDiscoveryServer, or a nonnumeric timestamp can abort the entire response. A principal that can register or update an instance can cause all connected Steeltoe clients to receive an empty or stale instance list until the malformed registration is removed. The JsonInstanceInfoConverter, BoolStringJsonConverter, and LongStringJsonConverter parsing paths are affected. This issue is distinct from the earlier DataCenterInfo.name parsing vulnerability. This issue is fixed in version 4.3.0.

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, 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.

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. From 4.0.0 until 4.3.0, EurekaDiscoveryClient deserializes the registry response as one unit, and an unrecognized actionType or status, a non-Boolean isCoordinatingDiscoveryServer, or a nonnumeric timestamp can abort the entire response. A principal that can register or update an instance can cause all connected Steeltoe clients to receive an empty or stale instance list until the malformed registration is removed. The JsonInstanceInfoConverter, BoolStringJsonConverter, and LongStringJsonConverter parsing paths are affected. This issue is distinct from the earlier DataCenterInfo.name parsing vulnerability. This issue is fixed in version 4.3.0.

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. From 4.0.0 until 4.3.0, EurekaDiscoveryClient deserializes the registry response as one unit, and an unrecognized actionType or status, a non-Boolean isCoordinatingDiscoveryServer, or a nonnumeric timestamp can abort the entire response. A principal that can register or update an instance can cause all connected Steeltoe clients to receive an empty or stale instance list until the malformed registration is removed. The JsonInstanceInfoConverter, BoolStringJsonConverter, and LongStringJsonConverter parsing paths are affected. This issue is distinct from the earlier DataCenterInfo.name parsing vulnerability. This issue is fixed in version 4.3.0.

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, 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.