Vulnerability-Lookup

FKIE_CVE-2021-25740

Vulnerability from fkie_nvd - Published: 2021-09-20 17:15 - Updated: 2026-06-17 03:42

Severity

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

Summary

A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.

References

URL	Tags
jordan@liggitt.net	https://github.com/kubernetes/kubernetes/issues/103675	Mitigation, Third Party Advisory
jordan@liggitt.net	https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE	Mailing List, Mitigation, Third Party Advisory
jordan@liggitt.net	https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/
jordan@liggitt.net	https://security.netapp.com/advisory/ntap-20211014-0001/	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://github.com/kubernetes/kubernetes/issues/103675	Mitigation, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE	Mailing List, Mitigation, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://security.netapp.com/advisory/ntap-20211014-0001/	Third Party Advisory

Impacted products

	Vendor	Product	Version
	kubernetes	kubernetes	-

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Kubernetes",
          "vendor": "Kubernetes",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "jordan@liggitt.net"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:kubernetes:kubernetes:-:*:*:*:*:*:*:*",
              "matchCriteriaId": "14C32308-314D-4E0D-B15F-6A68DF21E9F9",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack."
    },
    {
      "lang": "es",
      "value": "Se ha detectado un problema de seguridad en Kubernetes que podr\u00eda permitir a usuarios enviar tr\u00e1fico de red a lugares a los que de otro modo no tendr\u00edan acceso por medio de un ataque de tipo confused deputy"
    }
  ],
  "id": "CVE-2021-25740",
  "lastModified": "2026-06-17T03:42:22.997",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "SINGLE",
          "availabilityImpact": "NONE",
          "baseScore": 3.5,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "NONE",
          "vectorString": "AV:N/AC:M/Au:S/C:P/I:N/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 6.8,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.1,
          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 1.4,
        "source": "jordan@liggitt.net",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.1,
          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 1.4,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2021-09-20T17:15:08.283",
  "references": [
    {
      "source": "jordan@liggitt.net",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://github.com/kubernetes/kubernetes/issues/103675"
    },
    {
      "source": "jordan@liggitt.net",
      "tags": [
        "Mailing List",
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE"
    },
    {
      "source": "jordan@liggitt.net",
      "url": "https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/"
    },
    {
      "source": "jordan@liggitt.net",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.netapp.com/advisory/ntap-20211014-0001/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://github.com/kubernetes/kubernetes/issues/103675"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://security.netapp.com/advisory/ntap-20211014-0001/"
    }
  ],
  "sourceIdentifier": "jordan@liggitt.net",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-441"
        }
      ],
      "source": "jordan@liggitt.net",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-610"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2021-25740 (GCVE-0-2021-25740)

Vulnerability from cvelistv5 – Published: 2021-09-20 17:05 – Updated: 2026-06-01 21:45

Title

Holes in EndpointSlice Validation Enable Host Network Hijack

Summary

A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.

Severity

3.1 (Low)


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

CWE

CWE-441 - Unintended Proxy or Intermediary

Assigner

kubernetes mitre root Scorecard

References

4 references

URL	Tags
https://kubernetes.io/blog/2026/05/26/reconciling…	x_refsource_MISC
https://groups.google.com/g/kubernetes-security-a…	x_refsource_MISC
https://github.com/kubernetes/kubernetes/issues/103675	x_refsource_MISC
https://security.netapp.com/advisory/ntap-2021101…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
Kubernetes	Kubernetes	Affected: 0 , < * (semver)

Date Public

2021-07-14 00:00

Credits

Rob Scott

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T20:11:27.960Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/kubernetes/kubernetes/issues/103675"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20211014-0001/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Kubernetes",
          "vendor": "Kubernetes",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Rob Scott"
        }
      ],
      "datePublic": "2021-07-14T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.1,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-441",
              "description": "CWE-441 Unintended Proxy or Intermediary",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-01T21:45:55.645Z",
        "orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
        "shortName": "kubernetes"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/kubernetes/kubernetes/issues/103675"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://security.netapp.com/advisory/ntap-20211014-0001/"
        }
      ],
      "source": {
        "defect": [
          "https://github.com/kubernetes/kubernetes/issues/103675"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Holes in EndpointSlice Validation Enable Host Network Hijack",
      "x_generator": {
        "engine": "Vulnogram 0.0.9"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
    "assignerShortName": "kubernetes",
    "cveId": "CVE-2021-25740",
    "datePublished": "2021-09-20T17:05:18.065Z",
    "dateReserved": "2021-01-21T00:00:00.000Z",
    "dateUpdated": "2026-06-01T21:45:55.645Z",
    "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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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FKIE_CVE-2021-25740

CVE-2021-25740 (GCVE-0-2021-25740)

Tags

Sightings

Nomenclature

Related by attack behaviour