Medium severity · published Sep 16, 2025
CVE-2025-9708
Kubernetes C# Client: improper certificate validation in custom CA mode may lead to man-in-the-middle attacks
6.8
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KC
Kubernetes CSharp Client · Kubernetes
through 17.0.13 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-9708
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-9708
github.com
https://github.com/kubernetes/kubernetes/issues/134063
groups.google.com
https://groups.google.com/g/kubernetes-security-announce/c/rLopt2Msvbw/m/rK6XeNw2CgAJ
www.openwall.com
http://www.openwall.com/lists/oss-security/2025/09/16/1
