diff --git a/broker/src/main/java/io/moquette/persistence/MemoryMessagesStore.java b/broker/src/main/java/io/moquette/persistence/MemoryMessagesStore.java
index bba4f581..7d4f9ccf 100755
--- a/broker/src/main/java/io/moquette/persistence/MemoryMessagesStore.java
+++ b/broker/src/main/java/io/moquette/persistence/MemoryMessagesStore.java
@@ -2271,6 +2271,10 @@ public class MemoryMessagesStore implements IMessagesStore {
 
     @Override
     public ErrorCode blackUserRequest(String fromUser, String targetUserId, int state, long[] heads) {
+        if(state != 0 && state != 1 && state != 2){
+            return ErrorCode.INVALID_PARAMETER;
+        }
+
         if (state == 2) {
             state = 1;
         }