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GHSA-wqcw-g35j-j578

MEDIUMFix: kubewarden/docs#737

GHSA-wqcw-g35j-j578 is a medium-severity (CVSS 4.3) vulnerability in github.com/kubewarden/kubewarden-controller. O3 Security confirms whether GHSA-wqcw-g35j-j578 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Kubewarden vulnerable to RBAC Reconnaissance via unchecked can_i host capability call

Also known asCVE-2026-42541GO-2026-5716
Published
May 5, 2026
Updated
Jun 25, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed

Real-World Exposure

1 pkg affected
🐹github.com/kubewarden/kubewarden-controller

Real-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

Kubewarden is a policy engine for Kubernetes. Kubewarden cluster operators can grant permissions to users to deploy namespaced AdmissionPolicies and AdmissionPolicyGroups in their Namespaces. One of Kubewarden promises is that configured users can deploy namespaced policies in a safe manner, without privilege escalation.

An attacker with privileged AdmissionPolicy or AdmissionPolicyGroup create permissions (which isn't the default) can craft a policy that makes use of the can_i host callback. The callback issues a SubjectAccessReview (SAR) requests to enumerate RBAC permissions of any user or service account across the cluster. Three operations on the host capabilities kubewarden/kubernetes binding enforce the context-aware allow-list via can_access_kubernetes_resource():

  • list_resources_by_namespace
  • list_resources_all
  • get_resource

However, can_i does not perform that check and forwards the request directly to the callback handler, which executes a real SubjectAccessReview using policy-server privileges. This creates a policy-level authorization gap: can_i is effectively usable even when the policy has no context-aware resource grant.

This is an information disclosure / reconnaissance issue, and not direct workload data exfiltration. The attacker learns permission information, such as whether specific service accounts can "get secrets", "create pods", or "bind clusterroles" in chosen namespaces.

Patches

Cluster Operators, if providing their users with privileges to deploy AdmissionPolicies or AdmissionPolicygroups (which isn't the default), must then also deploy PolicyServers with reduced permissions for host capability calls. This includes the PolicyServer default. For that, make use of the new feature in v1.35:

  • For custom PolicyServers: Set the new PolicyServer.spec.namespacedPoliciesCapabilities , for example to an empty list [] which doesn't allow any capability.
  • For the default PolicyServer, set the .Values.policyServer.namespacedPoliciesCapabilities , for example to an empty list [] which doesn't allow any capability.

Also, if needed, they must ensure that those namespaced AdmissionPolicies or AdmissionPolicygroups are scheduled in the PolicyServers with reduced permissions. For that, they could make use of the new ns-policyserver-mapper policy, their own policy or other means, such as GitOps.

See: https://docs.kubewarden.io/howtos/policy-servers/namespaced-policies-capabilities

Workarounds

Cluster Operators can opt for:

  • Not allowing users to create namespaced policies (AdmissionPolicies, AdmissionPolicyGroups).
  • Removing SubjectAccessReview "create" permissions for the PolicyServer ServiceAccount RBAC being used, in custom PolicyServers and the PolicyServer default.

Resources

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/kubewarden/kubewarden-controllerall versions1.35.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Fix

    Update github.com/kubewarden/kubewarden-controller to 1.35.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wqcw-g35j-j578 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-wqcw-g35j-j578 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-wqcw-g35j-j578. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact Kubewarden is a policy engine for Kubernetes. Kubewarden cluster operators can grant permissions to users to deploy namespaced AdmissionPolicies and AdmissionPolicyGroups in their Namespaces. One of Kubewarden promises is that configured users can deploy namespaced policies in a safe manner, without privilege escalation. An attacker with privileged AdmissionPolicy or AdmissionPolicyGroup create permissions (which isn't the default) can craft a policy that makes use of the `can_i` host callback. The callback issues a SubjectAccessReview (SAR) requests to enumerate RBAC permissions o
O3 Security · Impact-Aware SCA

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