diff --git a/nbt/src/main/java/net/md_5/bungee/nbt/type/ListTag.java b/nbt/src/main/java/net/md_5/bungee/nbt/type/ListTag.java
index b1b591b8..87838329 100644
--- a/nbt/src/main/java/net/md_5/bungee/nbt/type/ListTag.java
+++ b/nbt/src/main/java/net/md_5/bungee/nbt/type/ListTag.java
@@ -33,6 +33,11 @@ public class ListTag implements TypedTag
         listType = input.readByte();
         int length = input.readInt();
 
+        if ( length < 0 )
+        {
+            throw new NBTFormatException( "ListTag length cannot be negative" );
+        }
+
         if ( listType == Tag.END && length > 0 )
         {
             throw new NBTFormatException( "Missing type in ListTag" );
diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/ProtocolConstants.java b/protocol/src/main/java/net/md_5/bungee/protocol/ProtocolConstants.java
index 99adad59..82d5f1e8 100644
--- a/protocol/src/main/java/net/md_5/bungee/protocol/ProtocolConstants.java
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/ProtocolConstants.java
@@ -50,7 +50,7 @@ public class ProtocolConstants
     public static final int MINECRAFT_1_21_2 = 768;
     public static final int MINECRAFT_1_21_4 = 769;
     public static final int MINECRAFT_1_21_5 = 770;
-    public static final int MINECRAFT_1_21_6 = 1073742076;
+    public static final int MINECRAFT_1_21_6 = 1073742078;
     public static final List<String> SUPPORTED_VERSIONS;
     public static final List<Integer> SUPPORTED_VERSION_IDS;