{"id":"CVE-2021-25736","state":"PUBLISHED","title":"Windows kube-proxy LoadBalancer contention","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.","publishedAt":"2023-10-30T02:19:48.916Z","updatedAt":"2025-06-12T14:42:12.231Z","severity":{"score":5.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","source":"kubernetes"},"assigner":"kubernetes","products":["Kubernetes Kubernetes"],"affected":[{"vendor":"Kubernetes","product":"Kubernetes","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"v1.20.5","versionType":"v1.20.5"}],"modules":["Kube-Proxy"],"platforms":["Windows"],"repo":"https://github.com/kubernetes/kubernetes"}],"references":["https://github.com/kubernetes/kubernetes/pull/99958","https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ","https://security.netapp.com/advisory/ntap-20231221-0003/"],"weaknesses":["CWE-114"],"ingestedAt":"2026-10-29T19:48:10.461Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/25xxx/CVE-2021-25736.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2021-25736","state":"PUBLISHED","datePublished":"2023-10-30T02:19:48.916Z","dateUpdated":"2025-06-12T14:42:12.231Z","assignerShortName":"kubernetes","assignerOrgId":"a6081bf6-c852-4425-ad4f-a67919267565","dateReserved":"2021-01-21T21:42:58.237Z"},"containers":{"cna":{"title":"Windows kube-proxy LoadBalancer contention","descriptions":[{"lang":"en","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."}],"affected":[{"vendor":"Kubernetes","product":"Kubernetes","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"v1.20.5","versionType":"v1.20.5"}],"modules":["Kube-Proxy"],"platforms":["Windows"],"repo":"https://github.com/kubernetes/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/"}],"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":{"shortName":"kubernetes","orgId":"a6081bf6-c852-4425-ad4f-a67919267565","dateUpdated":"2023-12-21T22:06:17.289Z"},"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"}],"solutions":[{"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"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.1.0-dev"}},"adp":[{"title":"CVE Program Container","references":[{"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/","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-03T20:11:28.044Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-06-12T14:39:48.612391Z","id":"CVE-2021-25736","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-114","type":"CWE","lang":"en","description":"CWE-114 Process Control"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-06-12T14:42:12.231Z"}}]}}}