Kong Ingress Controller for Kubernetes (KIC): Cross-namespace TLS Secret Exfiltration in Gateways with GatewayClass missing `konghq.com/gatewayclass-unmanaged: 'true'` annotation
Date: 2026-05
Affected: go/github.com/kong/kubernetes-ingress-controller, go/github.com/kong/kubernetes-ingress-controller/v2, go/github.com/kong/kubernetes-ingress-controller/v3
Attack vector: data-exfiltration
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-200

## Summary A vulnerability in the Kong Ingress Controller (KIC) allows for the unauthorized exfiltration of TLS certificates and private keys across Kubernetes namespace boundaries. In "managed" mode (where the `GatewayClass` lacks an unmanaged annotation), the Gateway TLS translator skips critical status checks. This bypass allows the translator to fetch Secrets from any namespace KIC watches, even when a `ReferenceGrant` explicitly denies access or is missing. An actor with RBAC permissions to create or modify Gateways in a low-privileged namespace can reference a Secret in a high-privileged namespace, causing KIC to "leak" that Secret's sensitive private key material into the Kong dataplane configuration. ## Am I affected? You are affected if all of these hold: 1. You are using Kong Ingress Controller with the **Gateway API**. 2. Your `GatewayClass` is operating in **managed mode** (default behavior, no unmanaged annotation). 3. KIC is configured to **watch multiple namespaces** (multi-tenant environment). 4. Users have RBAC permissions to `create` or `update` `gateways.gateway.networking.k8s.io` in their own namespaces. You are not affected if any of this: - You only use KIC for `Ingress` resources (not Gateway API). - Your `GatewayClass` uses the `konghq.com/gateway-unmanaged` annotation. - KIC is restricted via RBAC or configuration to only watch a single namespace. - You have strictly limited Gateway creation/modification permissions to trusted cluster administrat


Mitigations:

Architectural layers (MAESTRO):