diff --git a/DESCRIPTION b/DESCRIPTION
index aa0dcb5b6..ac0f58189 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: nanonext
 Type: Package
 Title: NNG (Nanomsg Next Gen) Lightweight Messaging Library
-Version: 0.10.4.9020
+Version: 0.10.4.9021
 Description: R binding for NNG (Nanomsg Next Gen), a successor to ZeroMQ. NNG is
     a socket library implementing 'Scalability Protocols', a reliable,
     high-performance standard for common communications patterns including
diff --git a/NEWS.md b/NEWS.md
index 2f5ea4e46..de94e3580 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,4 @@
-# nanonext 0.10.4.9020
+# nanonext 0.10.4.9021
 
 *This is a major stability release bundling the 'libnng' v1.6.0 source code.*
 
diff --git a/src/core.c b/src/core.c
index 231606f20..67e1563db 100644
--- a/src/core.c
+++ b/src/core.c
@@ -225,7 +225,8 @@ void nano_serialize_next(nano_buf *buf, SEXP object) {
   R_Serialize(object, &output_stream);
 
   if (registered && nano_refList != R_NilValue) {
-    *((uint64_t *) (buf->buf + 4)) = (uint64_t) buf->cur;
+    uint64_t cursor = (uint64_t) buf->cur;
+    memcpy(buf->buf + 4, &cursor, 8);
     SEXP call, out;
     PROTECT(call = Rf_lcons(nano_refHookIn, Rf_cons(nano_refList, R_NilValue)));
     PROTECT(out = Rf_eval(call, R_GlobalEnv));