diff --git a/cmd/kubeadm/app/apis/kubeadm/validation/validation.go b/cmd/kubeadm/app/apis/kubeadm/validation/validation.go
index f1a30a21086..56efee812d8 100644
--- a/cmd/kubeadm/app/apis/kubeadm/validation/validation.go
+++ b/cmd/kubeadm/app/apis/kubeadm/validation/validation.go
@@ -433,7 +433,6 @@ func isAllowedFlag(flagName string) bool {
 		kubeadmcmdoptions.KubeconfigDir,
 		kubeadmcmdoptions.UploadCerts,
 		kubeadmcmdoptions.ExperimentalUploadCerts,
-		kubeadmcmdoptions.CertificateKey,
 		"print-join-command", "rootfs", "v")
 	if knownFlags.Has(flagName) {
 		return true