What is Kubernetes security?

Kubernetes security encompasses the practices, tools, and configurations used to protect Kubernetes clusters, workloads, and data. It includes authentication, authorization (RBAC), network policies, pod security standards, secrets management, and runtime security.

What is the CKS certification?

The Certified Kubernetes Security Specialist (CKS) is a CNCF certification that validates expertise in securing Kubernetes clusters. It covers cluster setup and hardening, system hardening, minimizing microservice vulnerabilities, and supply chain security.

What are Kubernetes network policies?

Network policies are Kubernetes resources that control pod-to-pod and pod-to-external traffic. They act as a firewall for your cluster, allowing you to specify which pods can communicate with each other based on labels, namespaces, and ports.

What are Pod Security Standards?

Pod Security Standards (PSS) are predefined security profiles that define different levels of pod security restrictions: Privileged (unrestricted), Baseline (minimally restrictive to prevent known privilege escalations), and Restricted (heavily restricted following security best practices).

What is RBAC in Kubernetes?

Role-Based Access Control (RBAC) is a Kubernetes authorization mechanism that regulates access to resources based on user roles. It uses Role, ClusterRole, RoleBinding, and ClusterRoleBinding resources to define and assign permissions to users and service accounts.

How do I secure etcd in Kubernetes?

Secure etcd by enabling encryption at rest for secrets, using TLS for client-server communication, restricting access to etcd endpoints via firewall rules, enabling authentication, and running regular backups. etcd stores all cluster data including secrets.

What is a container escape attack?

A container escape attack occurs when a process breaks out of container isolation to access the host system or other containers. Common vectors include privileged containers, hostPath mounts, and kernel exploits. Mitigate with Pod Security Standards and seccomp profiles.

What tools are used for Kubernetes security scanning?

Popular Kubernetes security tools include Trivy (vulnerability scanning), Falco (runtime security), kube-bench (CIS benchmarks), OPA Gatekeeper and Kyverno (policy enforcement), Kubescape (security posture), and Cosign (image signing).

GHSA-pcx2-xcq4-65vf — APICall namespace isolation bypass via query string

CRITICALGHSA-pcx2-xcq4-65vf

Affected projects: kyverno
Disclosed: October 21, 2026
Last updated: October 23, 2026

Affected versions

Project	Vulnerable range
kyverno	`all versions`

Patched versions

Project	Fixed in
kyverno	`1.19.2`

References

GHSA-pcx2-xcq4-65vf

Summary

This advisory describes a bypass of the namespace isolation fix introduced in CVE-2026-22039. The original fix enforces that namespaced Kyverno policies can only access Kubernetes API resources within their own namespace by matching the URLPath against a namespace-extracting regular expression. However, this validation can be bypassed by embedding the namespace segment inside a query string parameter, exploiting a mismatch between how Go's path.Clean (which the validator uses) and net/url (which the HTTP execution layer uses) parse URLs containing ? separators. A user with permission to create a namespaced Policy can craft an APICall URLPath such as /api/v1/nodes?x=/namespaces/default/ that passes namespace validation but sends the actual request to a cluster-scoped endpoint.

Impact

A namespace-scoped user with create permission on policies.kyverno.io in their own namespace can reach any cluster-scoped or cross-namespace Kubernetes API endpoint using the Kyverno admission controller's ServiceAccount. The advisory describes the impact as: reading cluster-scoped resources such as nodes and ClusterRoles, reading secrets and other resources in arbitrary namespaces in violation of tenant isolation, and exfiltrating sensitive configuration that namespace boundaries are designed to protect. Reported by Akamai Security Group.

Detection

Review Kyverno Policy objects in all namespaces for context[].apiCall.urlPath values that contain ? or # characters. Any URLPath using query parameters or fragments to embed a namespace segment should be treated as suspicious. Monitor Kyverno admission controller logs for API requests made to cluster-scoped endpoints such as /api/v1/nodes when the issuing policy is namespace-scoped.

Mitigation

Upgrade Kyverno to version 1.19.2 or later. No workaround was published in the upstream advisory. Prior to upgrading, limit create permission on policies.kyverno.io to trusted users only in multi-tenant environments.

References

GHSA-pcx2-xcq4-65vf — GitHub Security Advisory

Affected versions

Patched versions

References

Summary​

Impact​

Detection​

Mitigation​

Related Security Guidance​

References​

Summary

Impact

Detection

Mitigation

Related Security Guidance

References