{"id":"CVE-2021-25736","aliases":["EUVD-2023-2624","GHSA-35c7-w35f-xwgh","GO-2023-2159","openSUSE-SU-2025:15424-1"],"status":"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.","severity":{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00915,"percentile":0.60641,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-114"],"published":"2023-10-30T02:19:48Z","modified":"2026-10-24T10:51:24Z","fixes":[{"ecosystem":"Go","package":"k8s.io/kubernetes","fixed_in":["1.21.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"k8s.io/kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.21.0"}]}]},{"source":"osv","ecosystem":"Go","package":"k8s.io/kubernetes","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.21.0"}]}]},{"source":"osv","ecosystem":"Go","package":"k8s.io/kubernetes","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.21.0"}]}]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"govulncheck-vulndb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.0.20250807T150727-1.1"}]}],"bundled":44}],"products":[{"vendor":"kubernetes","product":"kubernetes"}],"references":[{"url":"https://github.com/kubernetes/kubernetes/pull/99958","tags":["x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ","tags":["x_transferred","Mailing List","Third Party Advisory","advisory","web"]},{"url":"https://security.netapp.com/advisory/ntap-20231221-0003/","tags":["x_transferred","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-25736","tags":["advisory"]},{"url":"https://github.com/kubernetes/kubernetes/commit/b014610de3e5cf1bb0f7844b5758d29fc18b75e6","tags":["web"]},{"url":"https://security.netapp.com/advisory/ntap-20231221-0003","tags":["web"]},{"url":"https://github.com/advisories/GHSA-35c7-w35f-xwgh","tags":["advisory"]},{"url":"https://github.com/kubernetes/kubernetes","tags":["package"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2015-7561","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-9962","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-1000056","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-1002102","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-1002100","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-1002101","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-16733","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-19184","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2019-1002100","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2019-1002101","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2019-11245","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2019-11251","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2019-11253","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-26240","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-26241","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8551","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8555","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8557","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8558","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8562","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8563","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-8566","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-25735","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-25736","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-25737","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-25741","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-25743","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-30465","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2022-29162","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2022-29177","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2022-3162","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2022-3294","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-2431","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-25809","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-2727","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-2728","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-27561","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-28642","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-5528","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2024-45310","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2024-5321","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2025-3445","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2025-47907","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2025-47908","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2021-25736","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.","status":"published","published":"2023-10-30T02:19:48.916Z","modified":"2025-06-12T14:42:12.231Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-114"],"updated_at":"2026-11-02T14:32:59.430294Z"}],"euvd":[{"id":"EUVD-2023-2624","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.","status":"published","published":"2023-10-30T02:19:48Z","modified":"2025-06-12T14:42:12Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T20:32:24.598995Z"}],"ghsa":[{"id":"GHSA-35c7-w35f-xwgh","title":"Kube-proxy may unintentionally forward traffic","description":"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 \nwhere the LoadBalancer controller sets the `status.loadBalancer.ingress[].ip` field are unaffected.","status":"published","published":"2023-10-30T03:30:15Z","modified":"2026-07-06T16:26:45Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T14:40:39.314643Z"}],"nvd":[{"id":"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.","status":"published","published":"2023-10-30T03:15:07.653Z","modified":"2026-06-17T03:42:22.623Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-114"],"updated_at":"2026-11-02T14:07:07.764332Z"}],"osv":[{"id":"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.","status":"published","published":"2023-10-30T03:15:07.653Z","modified":"2026-10-24T10:51:24.42122429Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:18.778776Z"},{"id":"GHSA-35c7-w35f-xwgh","title":"Kube-proxy may unintentionally forward traffic","description":"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 \nwhere the LoadBalancer controller sets the `status.loadBalancer.ingress[].ip` field are unaffected.","status":"published","published":"2023-10-30T03:30:15Z","modified":"2026-09-10T03:50:03.384919778Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:46:35.050232Z"},{"id":"GO-2023-2159","title":"Kube-proxy may unintentionally forward traffic in k8s.io/kubernetes","description":"Kube-proxy may unintentionally forward traffic in k8s.io/kubernetes","status":"published","published":"2024-08-21T14:30:22Z","modified":"2026-02-04T03:26:10.362Z","updated_at":"2026-11-02T15:47:01.185262Z"},{"id":"openSUSE-SU-2025:15424-1","title":"govulncheck-vulndb-0.0.20250807T150727-1.1 on GA media","description":"These are all security issues fixed in the govulncheck-vulndb-0.0.20250807T150727-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2025-08-08T00:00:00Z","modified":"2026-03-23T04:53:45.821911Z","updated_at":"2026-11-02T16:58:37.810934Z"}]}}