How severe is CVE-2021-25736?

CVE-2021-25736 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-25736 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25736?

CVE-2021-25736 affects Kubernetes. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-25736?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-25736 published?

CVE-2021-25736 was published on 2023-10-30 and last updated on 2026-06-17.

CVE-2021-25736

CVE-2021-25736 is a medium-severity vulnerability in Kubernetes with a CVSS 3.x base score of 5.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-114.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-114
Affected product: Kubernetes
Published: 2023-10-30
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-25736?: 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.
How severe is CVE-2021-25736?: CVE-2021-25736 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-25736 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25736?: CVE-2021-25736 affects Kubernetes. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-25736?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-25736 published?: CVE-2021-25736 was published on 2023-10-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*

More vulnerabilities in Kubernetes

CVE-2018-1002105 — Critical (CVSS 9.8): In all Kubernetes versions prior to v1.10.11, v1.11.5, and v1.12.3, incorrect handling of error responses to proxied…
CVE-2017-1000056 — Critical (CVSS 9.8): Kubernetes version 1.5.0-1.5.4 is vulnerable to a privilege escalation in the PodSecurityPolicy admission plugin…
CVE-2016-1906 — Critical (CVSS 9.8): Openshift allows remote attackers to gain privileges by updating a build configuration that was created with an allowed…
CVE-2023-3955 — High (CVSS 8.8): A security issue was discovered in Kubernetes where a user that can create pods on Windows nodes may be able to…
CVE-2023-3676 — High (CVSS 8.8): A security issue was discovered in Kubernetes where a user that can create pods on Windows nodes may be able to…
CVE-2021-25741 — High (CVSS 8.8): A security issue was discovered in Kubernetes where a user may be able to create a container with subpath volume mounts…

All CVEs affecting Kubernetes →

Other CWE-114 vulnerabilities

CVE-2025-36250 — Critical (CVSS 10.0): IBM AIX 7.2, and 7.3 and IBM VIOS 3.1, and 4.1 NIM server (formerly known as NIM master) service (nimesis) could allow…
CVE-2024-56346 — Critical (CVSS 10.0): IBM AIX 7.2 and 7.3 nimesis NIM master service could allow a remote attacker to execute arbitrary commands due to…
CVE-2025-36251 — Critical (CVSS 9.6): IBM AIX 7.2, and 7.3 and IBM VIOS 3.1, and 4.1 nimsh service SSL/TLS implementations could allow a remote attacker to…
CVE-2024-56347 — Critical (CVSS 9.6): IBM AIX 7.2 and 7.3 nimsh service SSL/TLS protection mechanisms could allow a remote attacker to execute arbitrary…
CVE-2025-1950 — Critical (CVSS 9.3): IBM Hardware Management Console - Power Systems V10.2.1030.0 and V10.3.1050.0 could allow a local user to execute…
CVE-2024-25021 — High (CVSS 8.4): IBM AIX 7.3, VIOS 4.1's Perl implementation could allow a non-privileged local user to exploit a vulnerability to…

Browse all CWE-114 vulnerabilities →