GHSA-mxxc-p822-2hx9
Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/zalando/skipper | < 0.24.0 | 0.24.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### 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
References
External links from the advisory. They lead to third-party sites.
- https://github.com/zalando/skipper/security/advisories/GHSA-mxxc-p822-2hx9
- https://nvd.nist.gov/vuln/detail/CVE-2026-24470
- https://github.com/zalando/skipper/commit/a4c87ce029a58eb8e1c2c1f93049194a39cf6219
- https://github.com/zalando/skipper
- https://github.com/zalando/skipper/releases/tag/v0.24.0
- https://kubernetes.io/docs/concepts/services-networking/service/#externalname