CVE-2021-25735

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.

• CWE-372

• https://github.com/kubernetes/kubernetes/issues/100096Patch, Third Party Advisory
• https://groups.google.com/g/kubernetes-security-announce/c/FKAGqT4jx9YMailing List, Third Party Advisory
• https://github.com/kubernetes/kubernetes/issues/100096Patch, Third Party Advisory
• https://groups.google.com/g/kubernetes-security-announce/c/FKAGqT4jx9YMailing List, Third Party Advisory

Published

Sep 6, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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