diff --git a/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregatorFactory.java b/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregatorFactory.java
index 1e660f06f45..1b2d5fc1014 100644
--- a/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregatorFactory.java
+++ b/core/src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregatorFactory.java
@@ -31,7 +31,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 
-final class CardinalityAggregatorFactory extends ValuesSourceAggregatorFactory<ValuesSource> {
+final class CardinalityAggregatorFactory extends ValuesSourceAggregatorFactory.LeafOnly<ValuesSource> {
 
     private final long precisionThreshold;