FKIE_CVE-2021-25736

Vulnerability from fkie_nvd - Published: 2023-10-30 03:15 - Updated: 2026-06-17 03:42
Severity
5.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
6.3 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Summary
Kube-proxy on Windows can unintentionally forward traffic to local processes listening on the same port (“spec.ports[*].port”) as a LoadBalancer Service when the LoadBalancer controller does not set the “status.loadBalancer.ingress[].ip” field. Clusters where the LoadBalancer controller sets the “status.loadBalancer.ingress[].ip” field are unaffected.
References
jordan@liggitt.nethttps://github.com/kubernetes/kubernetes/pull/99958Third Party Advisory
jordan@liggitt.nethttps://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJMailing List, Third Party Advisory
jordan@liggitt.nethttps://security.netapp.com/advisory/ntap-20231221-0003/
af854a3a-2127-422b-91ae-364da2661108https://github.com/kubernetes/kubernetes/pull/99958Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20231221-0003/
Impacted products
Vendor Product Version
kubernetes kubernetes *
kubernetes kubernetes *
kubernetes kubernetes *
microsoft windows -
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "Kube-Proxy"
          ],
          "platforms": [
            "Windows"
          ],
          "product": "Kubernetes",
          "repo": "https://github.com/kubernetes/kubernetes",
          "vendor": "Kubernetes",
          "versions": [
            {
              "lessThanOrEqual": "v1.20.5",
              "status": "affected",
              "version": "0",
              "versionType": "v1.20.5"
            }
          ]
        }
      ],
      "source": "jordan@liggitt.net"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "8E811D79-831A-493A-A0C8-D06442D01ADD",
              "versionEndExcluding": "1.18.18",
              "versionStartIncluding": "1.18.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "54F99BEF-703E-43C0-846C-AB9EECE134A9",
              "versionEndExcluding": "1.19.10",
              "versionStartIncluding": "1.19.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "E26E82C1-754C-4E81-B7BC-FB4DACE33945",
              "versionEndExcluding": "1.20.6",
              "versionStartIncluding": "1.20.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        },
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*",
              "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA",
              "vulnerable": false
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ],
      "operator": "AND"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Kube-proxy\n on Windows can unintentionally forward traffic to local processes \nlistening on the same port (\u201cspec.ports[*].port\u201d) as a LoadBalancer \nService when the LoadBalancer controller\n does not set the \u201cstatus.loadBalancer.ingress[].ip\u201d field. Clusters \nwhere the LoadBalancer controller sets the \n\u201cstatus.loadBalancer.ingress[].ip\u201d field are unaffected."
    },
    {
      "lang": "es",
      "value": "Kube-proxy en Windows puede reenviar tr\u00e1fico involuntariamente a procesos locales que escuchan en el mismo puerto (\u201cspec.ports[*].port\u201d) que LoadBalancer Service cuando el controlador LoadBalancer no configura \u201cstatus.loadBalancer.ingress[].ip\u201d. Los cl\u00fasteres donde el controlador LoadBalancer establece el campo \"status.loadBalancer.ingress[].ip\" no se ven afectados."
    }
  ],
  "id": "CVE-2021-25736",
  "lastModified": "2026-06-17T03:42:22.623",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.3,
        "impactScore": 4.0,
        "source": "jordan@liggitt.net",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 4.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-25736",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2025-06-12T14:39:48.612391Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2023-10-30T03:15:07.653",
  "references": [
    {
      "source": "jordan@liggitt.net",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/kubernetes/kubernetes/pull/99958"
    },
    {
      "source": "jordan@liggitt.net",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
    },
    {
      "source": "jordan@liggitt.net",
      "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/kubernetes/kubernetes/pull/99958"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
    }
  ],
  "sourceIdentifier": "jordan@liggitt.net",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-114"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}



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