[Critical] GHSA-637c-6jxx-4rwm KEDA: Privilege escalation from namespace admin to cluster admin via KEDA TriggerAuthentication

Summary

A namespace admin who creates a TriggerAuthentication and a ScaledObject in their own namespace can make the KEDA operator send its own ServiceAccount token to a tenant-controlled URL. That token holds ["*"]/["*"] get cluster-wide, so it reads every Secret in every namespace, plus batch/jobs and horizontalpodautoscalers create/delete cluster-wide, */scale update on any workload, validatingwebhookconfigurations update (rewrite or disable cluster admission), and apiservices update (hijack aggregated API routing). This is effectively privilege escalation from namespace admin to cluster admin in real environments: a cluster-wide Secret read alone is enough to find a token for a more privileged ServiceAccount, and the cluster-wide batch/jobs create lets the attacker run a workload in any namespace whose Pod Security Admission level permits it (or that is PSA-exempt, such as kube-system , kyverno) to reach the node filesystem and a control-plane kubeconfig.

This is an incomplete fix of CVE-2025-68476: its content filter only requires the loaded file to be a JWT whose subject begins with system:serviceaccount:, which the operator's own projected token satisfies by construction. The destination field hashiCorpVault.address is unvalidated.

Finder credits: Artem Cherezov @cherez0ff, with Claude Opus 4.8

Verified live

kind v1.31.2, kedacore/keda v2.20.0 (latest at the time of audit, ) installed from the unmodified release manifest keda-2.20.0.yaml (ghcr.io/kedacore/keda:2.20.0), default settings.

Preconditions

The tenant holds create on triggerauthentications.keda.sh and scaledobjects.keda.sh in its own namespace (the documented KEDA tenant workflow), plus the built-in edit ClusterRole in that namespace. Often granted by a namespaced admin Role (--verb='*' --resource='*.*') in multi-tenant environments.
KEDA is installed with default settings.

Reproduction

Cluster preparation (not part of the attack)

kind create cluster --image kindest/node:v1.31.2 --name keda-poc --kubeconfig ./kubeconfig
export KUBECONFIG=./kubeconfig

# Install KEDA v2.20.0 (unmodified vendor release manifest).
curl -sSL -o keda-2.20.0.yaml https://github.com/kedacore/keda/releases/download/v2.20.0/keda-2.20.0.yaml
kubectl apply --server-side -f keda-2.20.0.yaml
kubectl wait --for=condition=Established crd/triggerauthentications.keda.sh crd/scaledobjects.keda.sh --timeout=120s
kubectl -n keda rollout status deploy/keda-operator --timeout=180s

# Tenant identity: namespace admin in tenant-a.
kubectl create namespace tenant-a
kubectl -n tenant-a create serviceaccount tenant
kubectl -n tenant-a create rolebinding tenant-edit --clusterrole=edit --serviceaccount=tenant-a:tenant
kubectl -n tenant-a create role tenant-keda --verb=create,get --resource=triggerauthentications.keda.sh,scaledobjects.keda.sh
kubectl -n tenant-a create rolebinding tenant-keda --role=tenant-keda --serviceaccount=tenant-a:tenant

# Mint a tenant kubeconfig from a real TokenRequest token.
SERVER=$(kubectl config view --minify -o jsonpath='{.clusters[0].cluster.server}')
CA=$(kubectl config view --minify --raw -o jsonpath='{.clusters[0].cluster.certificate-authority-data}')
TOKEN=$(kubectl -n tenant-a create token tenant --duration=24h)
cat > kubeconfig-tenant