CVE-2025-24376

kubewarden-controller is a Kubernetes controller that allows you to dynamically register Kubewarden admission policies. By design, AdmissionPolicy and AdmissionPolicyGroup can evaluate only namespaced resources. The resources to be evaluated are determined by the rules provided by the user when defining the policy. There might be Kubernetes namespaced resources that should not be validated by AdmissionPolicy and by the AdmissionPolicyGroup policies because of their sensitive nature. For example, PolicyReport are namespaced resources that contain the list of non compliant objects found inside of a namespace. An attacker can use either an AdmissionPolicy or an AdmissionPolicyGroup to prevent the creation and update of PolicyReport objects to hide non-compliant resources. Moreover, the same attacker might use a mutating AdmissionPolicy to alter the contents of the PolicyReport created inside of the namespace. Starting from the 1.21.0 release, the validation rules applied to AdmissionPolicy and AdmissionPolicyGroup have been tightened to prevent them from validating sensitive types of namespaced resources.

Weakness

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as wildcards or matching symbols when they are sent to a downstream component.

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

References

• https://github.com/kubewarden/kubewarden-controller/commit/8124039b5f0c955d0ee8c8ca12d4415282f02d2c
• https://github.com/kubewarden/kubewarden-controller/security/advisories/GHSA-fc89-jghx-8pvg