diff --git a/jetty-client/src/main/java/org/eclipse/jetty/client/util/BufferingResponseListener.java b/jetty-client/src/main/java/org/eclipse/jetty/client/util/BufferingResponseListener.java
index b15083973e4..e30c6b90155 100644
--- a/jetty-client/src/main/java/org/eclipse/jetty/client/util/BufferingResponseListener.java
+++ b/jetty-client/src/main/java/org/eclipse/jetty/client/util/BufferingResponseListener.java
@@ -103,10 +103,10 @@ public abstract class BufferingResponseListener extends Listener.Adapter
         int length = content.remaining();
         if (length>BufferUtil.space(buffer))
         {
-            int requiredCapacity = buffer.capacity()+length;
+            int requiredCapacity = buffer==null?0:buffer.capacity()+length;
             if (requiredCapacity>maxLength)
                 response.abort(new IllegalArgumentException("Buffering capacity exceeded"));
-
+            
             int newCapacity = Math.min(Integer.highestOneBit(requiredCapacity) << 1, maxLength);
             buffer = BufferUtil.ensureCapacity(buffer,newCapacity);
         }