CVE-2021-25736 MEDIUM

CVE-2021-25736: Windows kube-proxy LoadBalancer contention

Vendor Kubernetes
Product Kubernetes
Published October 30, 2023
Last update June 12, 2025
View on NVD All CVEs

CVSS base score

5.8/10
Attack vector Network
Attack complexity High
Privileges required High
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N

What the vulnerability does

01Description

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 where the LoadBalancer controller sets the “status.loadBalancer.ingress[].ip” field are unaffected.

Key dates

02Disclosure timeline

October 30, 2023 CVE published
June 12, 2025 Record updated