{"api_version":"1","generated_at":"2026-07-24T00:04:12+00:00","cve":"CVE-2021-25736","urls":{"html":"https://cve.report/CVE-2021-25736","api":"https://cve.report/api/cve/CVE-2021-25736.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-25736","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-25736"},"summary":{"title":"CVE-2021-25736","description":"Kube-proxy\n on Windows can unintentionally forward traffic to local processes \nlistening on the same port (“spec.ports[*].port”) as a LoadBalancer \nService when the LoadBalancer controller\n does not set the “status.loadBalancer.ingress[].ip” field. Clusters \nwhere the LoadBalancer controller sets the \n“status.loadBalancer.ingress[].ip” field are unaffected.","state":"PUBLIC","assigner":"security@kubernetes.io","published_at":"2023-10-30 03:15:00","updated_at":"2023-12-21 22:15:00"},"problem_types":["NVD-CWE-noinfo"],"metrics":[],"references":[{"url":"https://security.netapp.com/advisory/ntap-20231221-0003/","name":"https://security.netapp.com/advisory/ntap-20231221-0003/","refsource":"","tags":[],"title":"CVE-2021-25736 Kubernetes Vulnerability in NetApp Products | NetApp Product Security","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://github.com/kubernetes/kubernetes/pull/99958","name":"https://github.com/kubernetes/kubernetes/pull/99958","refsource":"MISC","tags":[],"title":"For LoadBalancer Service type don't create a HNS policy for empty or invalid external loadbalancer IP by sbangari · Pull Request #99958 · kubernetes/kubernetes · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ","name":"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ","refsource":"MISC","tags":[],"title":"[Security Advisory] CVE-2021-25736: Windows kube-proxy LoadBalancer contention","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-25736","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-25736","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"25736","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"kubernetes","cpe5":"kubernetes","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"25736","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"microsoft","cpe5":"windows","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-25736","qid":"995790","title":"GO (Go) Security Update for k8s.io/kubernetes (GHSA-35c7-w35f-xwgh)"}]},"source_records":{"cve_program":{"data_version":"4.0","data_type":"CVE","data_format":"MITRE","CVE_data_meta":{"ID":"CVE-2021-25736","ASSIGNER":"security@kubernetes.io","STATE":"PUBLIC"},"description":{"description_data":[{"lang":"eng","value":"Kube-proxy\n on Windows can unintentionally forward traffic to local processes \nlistening on the same port (“spec.ports[*].port”) as a LoadBalancer \nService when the LoadBalancer controller\n does not set the “status.loadBalancer.ingress[].ip” field. Clusters \nwhere the LoadBalancer controller sets the \n“status.loadBalancer.ingress[].ip” field are unaffected.\n\n"}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"n/a"}]}]},"affects":{"vendor":{"vendor_data":[{"vendor_name":"Kubernetes","product":{"product_data":[{"product_name":"Kubernetes","version":{"version_data":[{"version_affected":"<=","version_name":"0","version_value":"v1.20.5"}]}}]}}]}},"references":{"reference_data":[{"url":"https://github.com/kubernetes/kubernetes/pull/99958","refsource":"MISC","name":"https://github.com/kubernetes/kubernetes/pull/99958"},{"url":"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ","refsource":"MISC","name":"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ"}]},"generator":{"engine":"Vulnogram 0.1.0-dev"},"source":{"discovery":"UNKNOWN"},"solution":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>This issue has been fixed in the following versions:<u></u><u></u></p>\n<ul>\n<li>\nv1.21.0<u></u><u></u></li><li>\nv1.20.6<u></u><u></u></li><li>\nv1.19.10<u></u><u></u></li><li>\nv1.18.18</li></ul>"}],"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\n\n\n"}],"credits":[{"lang":"en","value":"Eric Paris "},{"lang":"en","value":"Christian Hernandez"}],"impact":{"cvss":[{"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"}]}},"nvd":{"publishedDate":"2023-10-30 03:15:00","lastModifiedDate":"2023-12-21 22:15:00","problem_types":["NVD-CWE-noinfo"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM"},"exploitabilityScore":1.8,"impactScore":4}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"AND","children":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*","versionStartIncluding":"1.18.0","versionEndExcluding":"1.18.18","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*","versionStartIncluding":"1.19.0","versionEndExcluding":"1.19.10","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*","versionStartIncluding":"1.20.0","versionEndExcluding":"1.20.6","cpe_name":[]}]},{"operator":"OR","children":[],"cpe_match":[{"vulnerable":false,"cpe23Uri":"cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*","cpe_name":[]}]}],"cpe_match":[]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"25736","Ordinal":"200562","Title":"CVE-2021-25736","CVE":"CVE-2021-25736","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"25736","Ordinal":"1","NoteData":"** RESERVED ** This candidate has been reserved by an organization or individual that will use it when announcing a new security problem. When the candidate has been publicized, the details for this candidate will be provided.","Type":"Description","Title":null}]}}}