--- a/net/minecraft/server/AttributeRanged.java
+++ b/net/minecraft/server/AttributeRanged.java
@@ -31,6 +31,8 @@
     }
 
     public double a(double d0) {
+        if (d0 != d0) return getDefault(); // CraftBukkit
+
         d0 = MathHelper.a(d0, this.a, this.maximum);
         return d0;
     }