GHSA-fc89-jghx-8pvg is a medium-severity (CVSS 6.5) CWE-155 vulnerability in github.com/kubewarden/kubewarden-controller. A fix is available for github.com/kubewarden/kubewarden-controller — see the affected versions and patch details below.
KubeWarden's AdmissionPolicy and AdmissionPolicyGroup policies can be used to alter PolicyReport resources
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-fc89-jghx-8pvg.
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.
How urgent is this, really
GHSA-fc89-jghx-8pvg plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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
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. See this section of Kubewarden’s documentation for more details about PolicyReport resources. 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.
Patches
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. The new validation will also restrict the usage of wildcards when defining apiGroups and resources rules for AdmissionPolicy and AdmissionPolicyGroup objects.
Workarounds
On clusters running Kubewarden < 1.21.0, the following Kubewarden policy can be applied to prevent the creation of AdmissionPolicy and AdmissionPolicyGroup resources that interact with PolicyReport resources:
apiVersion: policies.kubewarden.io/v1
kind: ClusterAdmissionPolicy
metadata:
name: "deny-interaction-with-policyreport"
spec:
module: registry://ghcr.io/kubewarden/policies/cel-policy:latest
settings:
variables:
- name: hasWildcardInsideOfApiGroup
expression: "object.spec.rules.exists(r, r.apiGroups.exists(ag, ag == '*'))"
- name: hasWildcardInsideOfResources
expression: "object.spec.rules.exists(r, r.resources.exists(ag, ag == '*' || ag == '*/*' || ag == 'policyreports/*'))"
- name: dealsWithPolicyReportApiGroup
expression: "object.spec.rules.exists(r, r.apiGroups.exists(ag, ag == 'wgpolicyk8s.io'))"
- name: dealsWithPolicyReportResource
expression: "object.spec.rules.exists(r, r.resources.exists(ag, ag == 'policyreports' || ag == 'policyreports/'))"
- name: isPendingDeletion
expression: "has(object.metadata.deletionTimestamp)"
validations:
- expression: |
!( variables.hasWildcardInsideOfApiGroup ||
variables.hasWildcardInsideOfResources ||
variables.dealsWithPolicyReportResource ||
variables.dealsWithPolicyReportApiGroup
) || variables.isPendingDeletion
message: "cannot target PolicyReport resources or use wildcards in apiGroups or resources"
rules:
- apiGroups: ["policies.kubewarden.io"]
apiVersions: ["v1"]
operations: ["CREATE", "UPDATE"]
resources: ["admissionpolicies", "admissionpolicygroups"]
mutating: false
backgroundAudit: true
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 | ≥ 1.7.0&&< 1.21.0 | 1.21.0go get github.com/kubewarden/kubewarden-controller@v1.21.0 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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-fc89-jghx-8pvg 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-fc89-jghx-8pvg can be triaged on real exposure rather than presence alone.
Tailored to GHSA-fc89-jghx-8pvg. 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-fc89-jghx-8pvg in your dependencies?
O3 Security finds GHSA-fc89-jghx-8pvg across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.