# CVE-2021-25735

## Summary

- **CVE ID:** CVE-2021-25735
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H)
- **CWE:** CWE-372
- **Published:** Sep 6, 2021
- **Last Modified:** Mar 13, 2026

## Description

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.

## Affected Products

- Kubernetes — Kubernetes (unspecified)

## References

- [CNA](https://groups.google.com/g/kubernetes-security-announce/c/FKAGqT4jx9Y)
- [CNA](https://github.com/kubernetes/kubernetes/issues/100096)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 5.52%
- **EPSS Percentile:** 92.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._