{"id":"CVE-2021-25740","aliases":["AZL-89312","DEBIAN-CVE-2021-25740","EUVD-2021-2120","GHSA-vw47-mr44-3jf9","OESA-2022-2139","UBUNTU-CVE-2021-25740"],"status":"published","title":"Holes in EndpointSlice Validation Enable Host Network Hijack","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","severity":{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.02191,"percentile":0.82681,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-441","CWE-610"],"published":"2021-09-20T17:05:18Z","modified":"2026-11-05T05:40:51Z","fixes":[{"ecosystem":"Debian:12","package":"kubernetes","fixed_in":["1.20.5+really1.20.2-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"kubernetes","fixed_in":["1.20.5+really1.20.2-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"kubernetes","fixed_in":["1.20.5+really1.20.2-1"],"sources":["osv"]},{"ecosystem":"openEuler:20.03-LTS-SP1","package":"kubernetes","fixed_in":["1.20.2-16.oe1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"k8s.io/kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.22.2"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.30.10-32"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.5+really1.20.2-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.5+really1.20.2-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.5+really1.20.2-1"}]}]},{"source":"osv","ecosystem":"Go","package":"k8s.io/kubernetes","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"1.22.2"}]}]},{"source":"osv","ecosystem":"openEuler:20.03-LTS-SP1","package":"kubernetes","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.2-16.oe1"}]}]}],"products":[{"vendor":"kubernetes","product":"kubernetes"}],"references":[{"url":"https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/","tags":["x_refsource_MISC"]},{"url":"https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE","tags":["x_refsource_MISC","x_transferred","Mailing List","Mitigation","Third Party Advisory","advisory","web"]},{"url":"https://github.com/kubernetes/kubernetes/issues/103675","tags":["x_refsource_MISC","x_transferred","Mitigation","Third Party Advisory","report","web"]},{"url":"https://security.netapp.com/advisory/ntap-20211014-0001/","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-25740","tags":["web","advisory"]},{"url":"https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves","tags":["web"]},{"url":"https://security.netapp.com/advisory/ntap-20211014-0001","tags":["web"]},{"url":"https://github.com/advisories/GHSA-vw47-mr44-3jf9"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-25740","tags":["advisory"]},{"url":"https://github.com/kubernetes/kubernetes","tags":["package"]},{"url":"https://www.openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-2139","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-25740","tags":["report"]},{"url":"https://www.openwall.com/lists/oss-security/2021/07/14/1","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-25740","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-25740","title":"Holes in EndpointSlice Validation Enable Host Network Hijack","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-20T17:05:18.065Z","modified":"2026-06-01T21:45:55.645Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-441"],"updated_at":"2026-11-02T14:32:59.802172Z"}],"euvd":[{"id":"EUVD-2021-2120","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-20T17:05:18Z","modified":"2026-06-01T21:45:55Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T18:20:57.453624Z"}],"ghsa":[{"id":"GHSA-vw47-mr44-3jf9","title":"Confused Deputy in 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attack.","status":"published","published":"2021-09-20T17:15:08.283Z","modified":"2026-06-17T03:42:22.997Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary"},{"version":"2.0","score":3.5,"vector":"AV:N/AC:M/Au:S/C:P/I:N/A:N","level":"low","assessor":"primary"}],"cwes":["CWE-441","CWE-610"],"updated_at":"2026-11-02T14:06:58.933037Z"}],"osv":[{"id":"AZL-89312","title":"CVE-2021-25740 affecting package kubernetes 1.30.10-32","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-20T17:15:08Z","modified":"2026-11-05T05:40:51Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-05T16:41:25.436971Z"},{"id":"CVE-2021-25740","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-20T17:15:08.283Z","modified":"2026-03-14T01:43:52.452369Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:44:18.778776Z"},{"id":"DEBIAN-CVE-2021-25740","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-20T17:15:08.283Z","modified":"2026-10-23T18:02:57.606951826Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:45:34.637046Z"},{"id":"GHSA-vw47-mr44-3jf9","title":"Confused Deputy in Kubernetes","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"published","published":"2021-09-21T18:28:30Z","modified":"2026-09-10T03:49:08.832153636Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-441","CWE-610"],"updated_at":"2026-11-02T15:46:57.694388Z"},{"id":"OESA-2022-2139","title":"kubernetes security update","description":"Container cluster management.\r\n\r\nSecurity Fix(es):\r\n\r\nA security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.(CVE-2021-25740)","status":"published","published":"2022-12-17T11:05:27Z","modified":"2026-08-18T01:17:28.176146776Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:52:39.934788Z"},{"id":"UBUNTU-CVE-2021-25740","description":"A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.","status":"withdrawn","published":"2021-09-20T17:15:00Z","modified":"2025-07-14T06:45:34.067098Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"},{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:54:26.779273Z"}]}}