Medium
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-25736
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 08:57 UTC · Revision 1
Source evidence
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.
osv:CVE-2021-25736
Complete source record
{
"id": "77e9d81c3e374414111fa73867a6cf36f725509305fe496d8c60101ed189ace9",
"url": "https://osv.dev/vulnerability/CVE-2021-25736",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-25736",
"summary": "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.",
"evidence": "osv:CVE-2021-25736",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-25736",
"aliases": [
"CVE-2021-25736",
"GHSA-35c7-w35f-xwgh",
"GO-2023-2159"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/kubernetes/kubelet",
"type": "GIT",
"events": [
{
"introduced": "f0d06ae44a2e7ef0c05aecb6e7773222947dd156"
},
{
"fixed": "91407aecd4edbe8888bb4648ee46e8dae792a20d"
},
{
"introduced": "1af8853567a0faecc59fbc4d7d2ddc9359ddde83"
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{
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{
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},
{
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}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "1.18.0"
},
{
"fixed": "1.18.18"
}
],
"source": "CPE_RANGE"
},
{
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"range": [
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"source": "CPE_RANGE"
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{
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{
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],
"source": "CPE_RANGE"
}
]
}
}
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-25736.json"
}
},
{
"ranges": [
{
"repo": "https://github.com/kubernetes/kubernetes",
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"events": [
{
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{
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{
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{
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},
{
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{
"fixed": "8a62859e515889f07e3e3be6a1080413f17cf2c3"
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],
"database_specific": {
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{
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{
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{
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],
"source": "CPE_RANGE"
},
{
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{
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{
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],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*",
"range": [
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{
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],
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}
],
"versions": [
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"v1.20.1",
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"v1.20.0",
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"v1.18.11-rc.0",
"v1.18.10",
"v1.19.4-rc.0",
"v1.19.3",
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"v1.19.3-rc.0",
"v1.18.9",
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"v1.19.1",
"v1.19.1-rc.0",
"v1.19.0",
"v1.18.9-rc.0",
"v1.18.8",
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"v1.18.7-rc.0",
"v1.18.6",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-25736.json"
}
}
],
"modified": "2026-10-24T10:51:24.421224290Z",
"provider": "osv",
"references": [
"https://github.com/kubernetes/kubernetes/pull/99958",
"https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q/m/O15LOazPAgAJ",
"https://security.netapp.com/advisory/ntap-20231221-0003/"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-25736",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 442590,
"published_at": "2023-10-30T03:15:07.653+00:00"
}