CVE-2021-25736

MEDIUM5.8EPSS 0.09%

Kube-proxy may unintentionally forward traffic

Published: 10/30/2023Modified: 2/4/2026

Also known as:GHSA-35c7-w35f-xwghCGA-g7x6-8ch3-6hqwGO-2023-2159

Description

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.

Affected packages (2)

Go/k8s.io/kubernetesfrom 0, < 1.21
Go/k8s.io/kubernetesfrom 0, < 1.21.0

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	MEDIUM5.8	CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N

References (7)

ADVISORYhttps://github.com/advisories/GHSA-35c7-w35f-xwgh
ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-25736
PATCHhttps://github.com/kubernetes/kubernetes
WEBhttps://github.com/kubernetes/kubernetes/commit/b014610de3e5cf1bb0f7844b5758d29fc18b75e6
WEBhttps://github.com/kubernetes/kubernetes/pull/99958
WEBhttps://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ
WEBhttps://security.netapp.com/advisory/ntap-20231221-0003