CVE-2026-24470: Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName
Impact
When running Skipper as an Ingress controller, users with permissions to create an Ingress and a Service of type ExternalName can create routes that enable them to use Skipper's network access to reach internal services.
Patches
https://github.com/zalando/skipper/releases/tag/v0.24.0 disables Kubernetes ExternalName by default.
Workarounds
Developers can allow list targets of an ExternalName by using -kubernetes-only-allowed-external-names=true and allow list via regular expressions -kubernetes-allowed-external-name '^[a-z][a-z0-9-.]+[.].allowed.example$'
References
https://kubernetes.io/docs/concepts/services-networking/service/#externalname
Other sources
Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.24.0, when running Skipper as an Ingress controller, users with permissions to create an Ingress and a Service of type ExternalName can create routes that enable them to use Skipper's network access to reach internal services. Version 0.24.0 disables Kubernetes ExternalName by default. As a workaround, developers can allow list targets of an ExternalName and allow list via regular expressions.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-24470?
CVE-2026-24470 has a high severity as it allows unauthorized access to internal services.
How do I fix CVE-2026-24470?
To mitigate CVE-2026-24470, upgrade Skipper Ingress Controller to version 0.24.0 or later.
What can attackers do with CVE-2026-24470?
Attackers can exploit CVE-2026-24470 to access internal services by creating routes with permissions that shouldn't be granted.
Which versions of Skipper are affected by CVE-2026-24470?
Versions prior to 0.24.0 of the Skipper Ingress Controller are affected by CVE-2026-24470.
Is CVE-2026-24470 related to Kubernetes services?
Yes, CVE-2026-24470 involves the creation of Kubernetes ExternalName services that can be exploited.