diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/io/ByteArrayOutputStream.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/io/ByteArrayOutputStream.java
index d6b4c34aebbe..6208048b5d7d 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/io/ByteArrayOutputStream.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/io/ByteArrayOutputStream.java
@@ -91,7 +91,7 @@ private void checkSizeAndGrow(int extra) {
         throw new BufferOverflowException();
       }
       byte[] newBuf = new byte[(int) nextCapacity];
-      System.arraycopy(buf, 0, newBuf, 0, buf.length);
+      System.arraycopy(buf, 0, newBuf, 0, pos);
       buf = newBuf;
     }
   }