diff --git a/src/vnet/buffer.h b/src/vnet/buffer.h
index 50515c4..9e997b8 100644
--- a/src/vnet/buffer.h
+++ b/src/vnet/buffer.h
@@ -452,11 +452,10 @@
   /* size of L4 prototol header */
   u16 gso_l4_hdr_sz;
 
-  /* The union below has a u64 alignment, so this space is unused */
-  u32 __unused2[1];
-
   struct
   {
+    u16 unused;
+    u16 thread_next;
     u32 arc_next;
     u32 ed_out2in_nat_session_index;
   } nat;