GHSA-756x-m4mj-q96c
MEDIUMKubewarden-Controller information leak via AdmissionPolicyGroup Resource
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/kubewarden/kubewarden-controllerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The policy group feature, added to by the 1.17.0 release, introduced two new types of CRD: ClusterAdmissionPolicyGroup and AdmissionPolicyGroup. The former is cluster wide, while the latter is namespaced.
By being namespaced, the AdmissionPolicyGroup has a well constrained impact on cluster resources. Hence, it’s considered safe to allow non-admin users to create and manage these resources in the namespaces they own. Kubewarden policies can be allowed to query the Kubernetes API at evaluation time; these types of policies are called “context aware“. Context aware policies can perform list and get operations against a Kubernetes cluster. The queries are done using the ServiceAccount of the Policy Server instance that hosts the policy. That means that access to the cluster is determined by the RBAC rules that apply to that ServiceAccount. The AdmissionPolicyGroup CRD allowed the deployment of context aware policies. This could allow an attacker to obtain information about resources that are out of their reach, by leveraging a higher access to the cluster granted to the ServiceAccount token used to run the policy.
The impact of this vulnerability depends on the privileges that have been granted to the ServiceAccount used to run the Policy Server and assumes that users are using the recommended best practices of keeping the Policy Server's ServiceAccount least privileged. By default, the Kubewarden helm chart grants access to the following resources (cluster wide) only: Namespace, Pod, Deployment and Ingress.
Patches
Starting from the 1.21.0 release, the AdmissionPolicyGroup CRD does not allow the definition of context aware policies. No modifications are needed neither for performing the upgrade nor afterwards.
Workarounds
On clusters running Kubewarden < 1.21.0, the following Kubewarden policy can be applied to prevent the creation of AdmissionPolicyGroup resources that have access to Kubernetes resources:
apiVersion: policies.kubewarden.io/v1
kind: ClusterAdmissionPolicy
metadata:
name: "deny-admission-policy-groups-with-context-resources"
spec:
module: registry://ghcr.io/kubewarden/policies/cel-policy:latest
settings:
variables:
- name: hasContextAwareResources
expression: "object.spec.policies.exists(p, has(object.spec.policies[p].contextAwareResources))"
- name: isPendingDeletion
expression: "has(object.metadata.deletionTimestamp)"
validations:
- expression: "!variables.hasContextAwareResources || variables.isPendingDeletion"
message: "AdmissionPolicyGroup has contextAwareResources defined"
rules:
- apiGroups: ["policies.kubewarden.io"]
apiVersions: ["v1"]
operations: ["CREATE", "UPDATE"]
resources: ["admissionpolicygroups"]
mutating: false
backgroundAudit: true
Once the policy is applied, the Kubewarden Audit Scanner can be used to identify the AdmissionPolicyGroup policies that are violating this policy.
For more information
If you have any questions or comments about this advisory you can contact the Kubewarden team using the procedures described under the “security disclosure“ guidelines of the Kubewarden project.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/kubewarden/kubewarden-controller | ≥ 1.17.0&&< 1.21.0 | 1.21.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kubewarden/kubewarden-controller. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/kubewarden/kubewarden-controller to 1.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-756x-m4mj-q96c is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-756x-m4mj-q96c is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-756x-m4mj-q96c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-756x-m4mj-q96c in your dependencies?
O3 detects GHSA-756x-m4mj-q96c across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.