diff --git a/pkg/framework/plugins/nodeutilization/validation.go b/pkg/framework/plugins/nodeutilization/validation.go
index 6ac48b72af..885f1b63b1 100644
--- a/pkg/framework/plugins/nodeutilization/validation.go
+++ b/pkg/framework/plugins/nodeutilization/validation.go
@@ -63,6 +63,12 @@ func ValidateLowNodeUtilizationArgs(obj runtime.Object) error {
 		return err
 	}
 	if args.MetricsUtilization != nil {
+		if args.MetricsUtilization.Source == "" && !args.MetricsUtilization.MetricsServer {
+			return fmt.Errorf("metrics source is empty")
+		}
+		if args.MetricsUtilization.Source != "" && args.MetricsUtilization.Source != api.KubernetesMetrics && args.MetricsUtilization.Source != api.PrometheusMetrics {
+			return fmt.Errorf("unrecognized metrics source")
+		}
 		if args.MetricsUtilization.Source == api.KubernetesMetrics && args.MetricsUtilization.MetricsServer {
 			return fmt.Errorf("it is not allowed to set both %q source and metricsServer", api.KubernetesMetrics)
 		}
diff --git a/pkg/framework/plugins/nodeutilization/validation_test.go b/pkg/framework/plugins/nodeutilization/validation_test.go
index 1f82ccc5c4..a5cb810d33 100644
--- a/pkg/framework/plugins/nodeutilization/validation_test.go
+++ b/pkg/framework/plugins/nodeutilization/validation_test.go
@@ -203,6 +203,25 @@ func TestValidateLowNodeUtilizationPluginConfig(t *testing.T) {
 			},
 			errInfo: fmt.Errorf("it is not allowed to set both \"KubernetesMetrics\" source and metricsServer"),
 		},
+		{
+			name: "legacy metrics server without metrics source",
+			args: &LowNodeUtilizationArgs{
+				Thresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    20,
+					v1.ResourceMemory: 20,
+					extendedResource:  20,
+				},
+				TargetThresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    80,
+					v1.ResourceMemory: 80,
+					extendedResource:  80,
+				},
+				MetricsUtilization: &MetricsUtilization{
+					MetricsServer: true,
+				},
+			},
+			errInfo: nil,
+		},
 		{
 			name: "missing prometheus query",
 			args: &LowNodeUtilizationArgs{
@@ -242,6 +261,42 @@ func TestValidateLowNodeUtilizationPluginConfig(t *testing.T) {
 			},
 			errInfo: fmt.Errorf("prometheus configuration is not allowed to set when source is set to \"KubernetesMetrics\""),
 		},
+		{
+			name: "metrics utilization without metrics source",
+			args: &LowNodeUtilizationArgs{
+				Thresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    20,
+					v1.ResourceMemory: 20,
+					extendedResource:  20,
+				},
+				TargetThresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    80,
+					v1.ResourceMemory: 80,
+					extendedResource:  80,
+				},
+				MetricsUtilization: &MetricsUtilization{},
+			},
+			errInfo: fmt.Errorf("metrics source is empty"),
+		},
+		{
+			name: "unknown metrics source",
+			args: &LowNodeUtilizationArgs{
+				Thresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    20,
+					v1.ResourceMemory: 20,
+					extendedResource:  20,
+				},
+				TargetThresholds: api.ResourceThresholds{
+					v1.ResourceCPU:    80,
+					v1.ResourceMemory: 80,
+					extendedResource:  80,
+				},
+				MetricsUtilization: &MetricsUtilization{
+					Source: api.MetricsSource("UnknownMetrics"),
+				},
+			},
+			errInfo: fmt.Errorf("unrecognized metrics source"),
+		},
 	}
 
 	for _, testCase := range tests {