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Kubernetes C# client accepts certificates from any CA without properly verifying the trust chain

Moderate severity GitHub Reviewed Published Sep 17, 2025 to the GitHub Advisory Database • Updated Sep 17, 2025

Package

nuget KubernetesClient (NuGet)

Affected versions

< 17.0.14

Patched versions

17.0.14

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.

References

Published by the National Vulnerability Database Sep 16, 2025
Published to the GitHub Advisory Database Sep 17, 2025
Reviewed Sep 17, 2025
Last updated Sep 17, 2025

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(2nd percentile)

Weaknesses

Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate. Learn more on MITRE.

CVE ID

CVE-2025-9708

GHSA ID

GHSA-w7r3-mgwf-4mqq

Source code

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