Database/Container, Kubernetes & orchestration
Kyverno: NamespacedMutatingPolicy target expressions lack namespace checks, enabling cross-namespace mutation
Impact
CEL output from a NamespacedMutatingPolicy's targetMatchConstraints.expression is not checked against the policy's own namespace. A tenant can emit a literal target naming another tenant's object, and the cluster-wide background controller mutates it - adding attacker subjects to a RoleBinding, or rewriting Roles, NetworkPolicies and ConfigMaps. On a shared GPU cluster that is a direct path into another tenant's namespace: grant yourself a binding there, then read its secrets and run workloads against its quota and its GPUs. Rewriting NetworkPolicies also means tenant isolation on the fabric can be quietly loosened without the victim seeing a change they made.
Who can reach it
An authenticated namespace-scoped tenant who can create a NamespacedMutatingPolicy. Kubernetes API access only.
What to do
Upgrade Kyverno to 1.19.2 or later (affects 1.17.0 onwards) per the GitHub advisory. Controller rollout and pod restart, no node drain. Interim: prevent tenants from creating NamespacedMutatingPolicy objects, and audit RoleBindings and NetworkPolicies in tenant namespaces for unexpected mutations.
References
Related entries
- Kyverno: namespace-scoped policy escapes its namespace clamp and escalates to cluster adminCVE-2026-124440 · Kyverno admission controller (apiCall urlPath namespace clamp)Critical
- Harbor: Hard-coded default credentials give web UI access to the whole registryCVE-2026-4404 · HarborCritical
- Azure Kubernetes Service: incorrect authorization lets an authorized attacker elevate privileges remotelyCVE-2026-50516 · Microsoft Azure Kubernetes Service (authorization checks)Critical
- containerd: CRI plugin propagates unvalidated image LABEL values into container configCVE-2026-53488 · containerdCritical
- Dokploy: registry password and URL interpolated unescaped into a swarm deploy commandCVE-2026-72879 · Dokploy registry credential handling (getRegistryCommands in cluster/upload.ts)Critical
- Kyverno: overlapping PolicyExceptions let a tenant bypass an enforce-mode policyCVE-2026-84200 · Kyverno admission controller (PolicyException handling)Critical
This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.