CVE-2021-25737

Name: CVE-2021-25737
Creator: NVD / NIST
Published: 2021-09-06T12:15:07.673+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.8/10EPSS 1.29%

Last modified Jun 17, 2026

CVE-2021-25737 is a medium-severity vulnerability rated 4.8/10 on the CVSS scale. A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs.. EPSS estimates a 1.29% chance of exploitation in the next 30 days.

Description

A security issue was discovered in Kubernetes where a user may be able to redirect pod traffic to private networks on a Node. Kubernetes already prevents creation of Endpoint IPs in the localhost or link-local range, but the same validation was not performed on EndpointSlice IPs.

Metrics

CVSS 3.1

4.8/10

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

EPSS Probability

1.29%

66.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Kubernetes	Kubernetes	>= 1.16.0, < 1.18.19
Kubernetes	Kubernetes	>= 1.19.0, < 1.19.10
Kubernetes	Kubernetes	>= 1.20.0, < 1.20.7
Kubernetes	Kubernetes	1.21.0

References

https://github.com/kubernetes/kubernetes/issues/102106Patch, Third Party Advisory
https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thYMailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20211004-0004/Third Party Advisory
https://github.com/kubernetes/kubernetes/issues/102106Patch, Third Party Advisory
https://groups.google.com/g/kubernetes-security-announce/c/xAiN3924thYMailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20211004-0004/Third Party Advisory

Timeline

Published: Sep 6, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-25737?

How severe is CVE-2021-25737?

CVE-2021-25737 has a CVSS score of 4.8/10 (MEDIUM severity). The EPSS model estimates a 1.29% probability of exploitation in the next 30 days.

How do I fix CVE-2021-25737?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-25737?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST