GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-25736 (GCVE-0-2021-25736)

Vulnerability from cvelistv5 – Published: 2023-10-30 02:19 – Updated: 2025-06-12 14:42
VLAI
Title
Windows kube-proxy LoadBalancer contention
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.
Severity
5.8 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-06-12 14:39 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Kubernetes Kubernetes Affected: 0 , ≤ v1.20.5 (v1.20.5)
guessed Create a notification for this product.
Credits
Eric Paris Christian Hernandez
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T20:11:28.044Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/kubernetes/kubernetes/pull/99958"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-25736",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-06-12T14:39:48.612391Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-114",
                "description": "CWE-114 Process Control",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-06-12T14:42:12.231Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "user": "00000000-0000-4000-9000-000000000000",
          "value": "Eric Paris"
        },
        {
          "lang": "en",
          "type": "finder",
          "user": "00000000-0000-4000-9000-000000000000",
          "value": "Christian Hernandez"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003e\nKube-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.\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/p\u003e"
            }
          ],
          "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "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"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2023-12-21T22:06:17.289Z",
        "orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
        "shortName": "kubernetes"
      },
      "references": [
        {
          "url": "https://github.com/kubernetes/kubernetes/pull/99958"
        },
        {
          "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
        },
        {
          "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eThis issue has been fixed in the following versions:\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\nv1.21.0\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.20.6\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.19.10\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.18.18\u003c/li\u003e\u003c/ul\u003e"
            }
          ],
          "value": "This issue has been fixed in the following versions:\n\n\n\n  *  \nv1.21.0\n  *  \nv1.20.6\n  *  \nv1.19.10\n  *  \nv1.18.18"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Windows kube-proxy LoadBalancer contention",
      "x_generator": {
        "engine": "Vulnogram 0.1.0-dev"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
    "assignerShortName": "kubernetes",
    "cveId": "CVE-2021-25736",
    "datePublished": "2023-10-30T02:19:48.916Z",
    "dateReserved": "2021-01-21T21:42:58.237Z",
    "dateUpdated": "2025-06-12T14:42:12.231Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-25736",
      "date": "2026-09-19",
      "epss": "0.00915",
      "percentile": "0.58619"
    },
    "fkie_nvd": {
      "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"
        }
      ],
      "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.\n\n"
        },
        {
          "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": "2024-11-21T05:55:19.167",
      "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"
          }
        ]
      },
      "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"
        }
      ]
    },
    "nvd": {
      "cve": {
        "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": "2025-06-12T15:15:27.407",
        "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"
            }
          ]
        },
        "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"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-26T19:24:30+00:00",
      "cve": "CVE-2021-25736",
      "id": "CVE-2021-25736",
      "initial_release_date": "2021-05-10T00:00:00+00:00",
      "product_status:fixed": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kubernetes: LoadBalancer Service type don\u0027t create a HNS policy for empty or invalid external loadbalancer IP, what could lead to MITM",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-25736.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-01T01:39:54Z",
      "cve": "CVE-2021-25736",
      "id": "CVE-2021-25736",
      "initial_release_date": "2026-05-21T03:00:37Z",
      "product_status:known_not_affected": "52",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-25736",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-25736.json",
      "version": "6"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-03T20:11:28.044Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://github.com/kubernetes/kubernetes/pull/99958"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-25736",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-06-12T14:39:48.612391Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-114",
                    "description": "CWE-114 Process Control",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-06-12T14:42:03.979Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "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"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "user": "00000000-0000-4000-9000-000000000000",
              "value": "Eric Paris"
            },
            {
              "lang": "en",
              "type": "finder",
              "user": "00000000-0000-4000-9000-000000000000",
              "value": "Christian Hernandez"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003e\nKube-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.\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/p\u003e"
                }
              ],
              "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."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "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"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2023-12-21T22:06:17.289Z",
            "orgId": "a6081bf6-c852-4425-ad4f-a67919267565",
            "shortName": "kubernetes"
          },
          "references": [
            {
              "url": "https://github.com/kubernetes/kubernetes/pull/99958"
            },
            {
              "url": "https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"
            },
            {
              "url": "https://security.netapp.com/advisory/ntap-20231221-0003/"
            }
          ],
          "solutions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cp\u003eThis issue has been fixed in the following versions:\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\nv1.21.0\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.20.6\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.19.10\u003cu\u003e\u003c/u\u003e\u003cu\u003e\u003c/u\u003e\u003c/li\u003e\u003cli\u003e\nv1.18.18\u003c/li\u003e\u003c/ul\u003e"
                }
              ],
              "value": "This issue has been fixed in the following versions:\n\n\n\n  *  \nv1.21.0\n  *  \nv1.20.6\n  *  \nv1.19.10\n  *  \nv1.18.18"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "Windows kube-proxy LoadBalancer contention",
          "x_generator": {
            "engine": "Vulnogram 0.1.0-dev"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a6081bf6-c852-4425-ad4f-a67919267565",
        "assignerShortName": "kubernetes",
        "cveId": "CVE-2021-25736",
        "datePublished": "2023-10-30T02:19:48.916Z",
        "dateReserved": "2021-01-21T21:42:58.237Z",
        "dateUpdated": "2025-06-12T14:42:12.231Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


Detection rules are retrieved from Rulezet.


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.