In case you wonder about IngressNightmare and K3s https://kubernetes.io/blog/2025/03/24/ingress-nginx-cve-2025-1974/ the default Ingress with K3s is Traefik, so likely not impacted. Unless the default Ingress has been replaced, which is possible, which you can check using instructions from the announcement. First, determine if your clusters are using ingress-nginx. In most cases, you can check this by running

kubectl get pods --all-namespaces --selector <http://app.kubernetes.io/name=ingress-nginx|app.kubernetes.io/name=ingress-nginx>

with cluster administrator permissions.