{"id":"CVE-2021-25735","aliases":["GHSA-g42g-737j-qx6j","GO-2022-0907"],"url":"https://o3.security/vulnerability/CVE-2021-25735","summary":"Access Restriction Bypass in kube-apiserver","details":"A security issue was discovered in kube-apiserver that could allow node updates to bypass a Validating Admission Webhook. Clusters are only affected by this vulnerability if they run a Validating Admission Webhook for Nodes that denies admission based at least partially on the old state of the Node object. Validating Admission Webhook does not observe some previous fields.","published":"2021-09-06T12:15:07.617Z","modified":"2026-08-07T15:15:14.698043Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":2,"affectedPackages":[{"ecosystem":"Go","name":"k8s.io/kubernetes","fixedVersion":"1.20.6"},{"ecosystem":"Go","name":"k8s.io/kubernetes","fixedVersion":"1.19.10"},{"ecosystem":"Go","name":"k8s.io/kubernetes","fixedVersion":"1.18.18"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://groups.google.com/g/kubernetes-security-announce/c/FKAGqT4jx9Y"},{"type":"FIX","url":"https://github.com/kubernetes/kubernetes/issues/100096"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T15:15:14.698043Z"}}