Vulnerability-Lookup

GHSA-MXXC-P822-2HX9

Vulnerability from github – Published: 2026-01-26 23:26 – Updated: 2026-01-29 03:24

Summary

Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName

Details

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

Severity

8.1 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/zalando/skipper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.24.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-24470"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-441",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-26T23:26:56Z",
    "nvd_published_at": "2026-01-26T23:16:09Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nWhen 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\u0027s network access to reach internal services.\n\n### Patches\n\nhttps://github.com/zalando/skipper/releases/tag/v0.24.0 disables Kubernetes ExternalName by default.\n\n### Workarounds\n\nDevelopers 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 \u0027^[a-z][a-z0-9-.]+[.].allowed.example$\u0027` \n\n### References\n\nhttps://kubernetes.io/docs/concepts/services-networking/service/#externalname",
  "id": "GHSA-mxxc-p822-2hx9",
  "modified": "2026-01-29T03:24:42Z",
  "published": "2026-01-26T23:26:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/zalando/skipper/security/advisories/GHSA-mxxc-p822-2hx9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24470"
    },
    {
      "type": "WEB",
      "url": "https://github.com/zalando/skipper/commit/a4c87ce029a58eb8e1c2c1f93049194a39cf6219"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/zalando/skipper"
    },
    {
      "type": "WEB",
      "url": "https://github.com/zalando/skipper/releases/tag/v0.24.0"
    },
    {
      "type": "WEB",
      "url": "https://kubernetes.io/docs/concepts/services-networking/service/#externalname"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName"
}

CVE-2026-24470 (GCVE-0-2026-24470)

Vulnerability from cvelistv5 – Published: 2026-01-26 22:23 – Updated: 2026-01-27 14:51

Title

Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName

Summary

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.

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-27 14:50 UTC

CWE

CWE-441 - Unintended Proxy or Intermediary ('Confused Deputy')
CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/zalando/skipper/security/advis…	x_refsource_CONFIRM
https://github.com/zalando/skipper/commit/a4c87ce…	x_refsource_MISC
https://kubernetes.io/docs/concepts/services-netw…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
zalando	skipper	Affected: < 0.24.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-24470",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-27T14:50:06.337869Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-27T14:51:35.229Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "skipper",
          "vendor": "zalando",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.24.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u0027s 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-441",
              "description": "CWE-441: Unintended Proxy or Intermediary (\u0027Confused Deputy\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-26T22:23:43.325Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/zalando/skipper/security/advisories/GHSA-mxxc-p822-2hx9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/zalando/skipper/security/advisories/GHSA-mxxc-p822-2hx9"
        },
        {
          "name": "https://github.com/zalando/skipper/commit/a4c87ce029a58eb8e1c2c1f93049194a39cf6219",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/zalando/skipper/commit/a4c87ce029a58eb8e1c2c1f93049194a39cf6219"
        },
        {
          "name": "https://kubernetes.io/docs/concepts/services-networking/service/#externalname",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://kubernetes.io/docs/concepts/services-networking/service/#externalname"
        }
      ],
      "source": {
        "advisory": "GHSA-mxxc-p822-2hx9",
        "discovery": "UNKNOWN"
      },
      "title": "Skipper Ingress Controller Allows Unauthorized Access to Internal Services via ExternalName"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-24470",
    "datePublished": "2026-01-26T22:23:43.325Z",
    "dateReserved": "2026-01-23T00:38:20.546Z",
    "dateUpdated": "2026-01-27T14:51:35.229Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

GHSA-MXXC-P822-2HX9

Impact

Patches

Workarounds

References

CVE-2026-24470 (GCVE-0-2026-24470)

Tags

Sightings

Nomenclature

Related by attack behaviour