A vulnerability exists in the Kubernetes C# client where the certificate validation logic accepts properly constructed certificates from any Certificate Authority (CA) without properly verifying the trust chain. This flaw allows a malicious actor to present a forged certificate and potentially intercept or manipulate communication with the Kubernetes API server, leading to possible man-in-the-middle attacks and API impersonation.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-29657 Kubernetes C# client accepts certificates from any CA without properly verifying the trust chain
Github GHSA Github GHSA GHSA-w7r3-mgwf-4mqq Kubernetes C# client accepts certificates from any CA without properly verifying the trust chain
Fixes

Solution

Deploy the patch version of the Kubernetes C# client as soon as possible. Alternatively, move the CA certificates into the system trust store instead of specifying them in the kubeconfig file. Note: This approach may introduce new risks, as all processes on the system will begin to trust certificates signed by that CA. If you must use an affected version, you can disable custom CA and add the CA to the machine's trusted root.


Workaround

No workaround given by the vendor.

History

Wed, 17 Sep 2025 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 17 Sep 2025 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Kubernetes
Kubernetes kubernetes
Vendors & Products Kubernetes
Kubernetes kubernetes

Tue, 16 Sep 2025 21:30:00 +0000

Type Values Removed Values Added
Description A vulnerability exists in the Kubernetes C# client where the certificate validation logic accepts properly constructed certificates from any Certificate Authority (CA) without properly verifying the trust chain. This flaw allows a malicious actor to present a forged certificate and potentially intercept or manipulate communication with the Kubernetes API server, leading to possible man-in-the-middle attacks and API impersonation.
Title Kubernetes C# Client: improper certificate validation in custom CA mode may lead to man-in-the-middle attacks
Weaknesses CWE-295
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: kubernetes

Published:

Updated: 2025-09-17T13:42:59.781Z

Reserved: 2025-08-29T16:21:58.881Z

Link: CVE-2025-9708

cve-icon Vulnrichment

Updated: 2025-09-17T13:42:55.327Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-16T22:15:33.407

Modified: 2025-09-17T14:18:55.093

Link: CVE-2025-9708

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2025-09-17T10:52:06Z