Affected: Bitnami: kyverno

Kyverno is a policy engine designed for cloud native platform engineering teams. From 1.18.0 until 1.18.2, the NamespacedMutatingPolicy CEL compiler exposes the generator library to matchConditions, allowing a namespace-scoped policy to invoke generator.apply(namespace, resources) with an arbitrary target namespace. The validation in pkg/cel/policies/mpol/validate.go checks that the policy compiles but does not enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go does not reject the cross-namespace target. A user who can create NamespacedMutatingPolicy objects in one namespace can cause the admission controller, operating with cluster-wide privileges, to create ConfigMaps, NetworkPolicies, Secrets, RoleBindings, and other resources in another namespace, enabling unauthorized modification and potential privilege escalation. This issue is fixed in version 1.18.2.

Kyverno is a policy engine designed for cloud native platform engineering teams. From 1.18.0 until 1.18.2, the NamespacedMutatingPolicy CEL compiler exposes the generator library to matchConditions, allowing a namespace-scoped policy to invoke generator.apply(namespace, resources) with an arbitrary target namespace. The validation in pkg/cel/policies/mpol/validate.go checks that the policy compiles but does not enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go does not reject the cross-namespace target. A user who can create NamespacedMutatingPolicy objects in one namespace can cause the admission controller, operating with cluster-wide privileges, to create ConfigMaps, NetworkPolicies, Secrets, RoleBindings, and other resources in another namespace, enabling unauthorized modification and potential privilege escalation. This issue is fixed in version 1.18.2.

Affected: Go: github.com/kyverno/kyverno

## Summary

In Kyverno v1.18.1, a tenant who can create a `NamespacedMutatingPolicy` in their own namespace can instruct the admission controller to generate resources in any namespace by passing an arbitrary namespace string to the CEL `generator.apply(namespace, resources)` function.

## Details

`pkg/cel/libs/context.go:177` declares `GenerateResources(namespace string, dataList []map[string]any)`. The `namespace` argument arrives unvalidated from the CEL expression `generator.apply("<target-namespace>", [...])`.

### Version-Specific Impact

**v1.18.0, v1.18.1 (affected via NamespacedMutatingPolicy only):**

The nmpol CEL compiler unintentionally exposes the `generator` library to match condition expressions. A namespaced mutating policy can invoke `generator.apply()` in a boolean CEL expression such as `matchConditions`, triggering the admission controller to generate resources in any namespace at request time. This side effect executes with the admission controller's cluster-wide privileges.

NamespacedGeneratingPolicy is **not** a vector in v1.18.1 due to incomplete webhook and background processing wiring (not registered or functional).

### Root Cause

The admission validator for `NamespacedMutatingPolicy` (`pkg/cel/policies/mpol/validate.go`) only checks that the policy compiles and does not enforce namespace scope on `generator.apply()` arguments.

Compare correctly-guarded equivalents: `pkg/engine/context/loaders/configmap.go:102` rejects cross-namespace ConfigMa…

Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Kyverno ausnutzen, um seine Privilegien zu erhöhen.