CVE-2026-42541 Kubewarden: RBAC Reconnaissance via unchecked can_i host capability call

What is CVE-2026-42541?

CVE-2026-42541 is a medium-severity vulnerability in kubewarden-controller, published on 12 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Kubewarden is a policy engine for Kubernetes. Prior to , 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. can_i does not perform that check to enforce the context-aware allow-list 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. This vulnerability is fixed in .

Weakness: CWE-862

Which versions are affected by CVE-2026-42541?

3 open source packages ship an affected version, including github.com/kubewarden/kubewarden-controller.

How do I fix CVE-2026-42541?

Upgrade github.com/kubewarden/kubewarden-controller to 1.35.0 or later.

Is CVE-2026-42541 being exploited?

There is no known exploitation of CVE-2026-42541 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-wqcw-g35j-j578, GO-2026-5716.