CVE-2025-9708 Kubernetes C# Client: improper certificate validation in custom CA mode may lead to man-in-the-middle attacks
Attackers can intercept Kubernetes API traffic via man-in-the-middle attacks due to improper certificate validation in the C# client's custom CA mode.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-9708?
CVE-2025-9708 is a medium-severity vulnerability in Kubernetes CSharp Client, published on 16 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-295
Which versions are affected by CVE-2025-9708?
2 open source packages ship an affected version, including KubernetesClient.
| Package | Affected | Fixed in |
|---|---|---|
KubernetesClient NuGet | All versions | 17.0.14 |
KubernetesClient NuGet | All versions | 17.0.14 |
How do I fix CVE-2025-9708?
Upgrade KubernetesClient to 17.0.14 or later.
Is CVE-2025-9708 being exploited?
There is no known exploitation of CVE-2025-9708 in the wild and no public exploit code.
Sources
Also known as GHSA-w7r3-mgwf-4mqq.