diff --git a/poi/src/main/java/org/apache/poi/hpsf/ClassID.java b/poi/src/main/java/org/apache/poi/hpsf/ClassID.java
index 7c99b1c4c3..688fd6fa0c 100644
--- a/poi/src/main/java/org/apache/poi/hpsf/ClassID.java
+++ b/poi/src/main/java/org/apache/poi/hpsf/ClassID.java
@@ -153,7 +153,7 @@ public class ClassID implements Duplicatable, GenericRecord {
         /* Read 8 bytes. */
         System.arraycopy(src, 8 + offset, bytes, 8, 8);
 
-        return bytes;
+        return bytes.clone();
     }
 
     /**