size);
+	ATF_TP_ADD_TC(tp, nvlist_send_recv__overflow_little_endian_size);
 	ATF_TP_ADD_TC(tp, nvlist_send_recv__invalid_fd_size);
 	ATF_TP_ADD_TC(tp, nvlist_send_recv__overflow_fd_size);
 
diff --git a/sys/contrib/libnv/nvlist.c b/sys/contrib/libnv/nvlist.c
index 279f31e3a7cc..71fb52d9ee37 100644
--- a/sys/contrib/libnv/nvlist.c
+++ b/sys/contrib/libnv/nvlist.c
@@ -1028,10 +1028,6 @@ static bool
 nvlist_check_header(struct nvlist_header *nvlhdrp)
 {
 
-	if (nvlhdrp->nvlh_size > SIZE_MAX - sizeof(*nvlhdrp)) {
-		ERRNO_SET(EINVAL);
-		return (false);
-	}
 	if (nvlhdrp->nvlh_magic != NVLIST_HEADER_MAGIC) {
 		ERRNO_SET(EINVAL);
 		return (false);
@@ -1051,6 +1047,11 @@ nvlist_check_header(struct nvlist_header *nvlhdrp)
 		nvlhdrp->nvlh_descriptors = be64toh(nvlhdrp->nvlh_descriptors);
 	}
 #endif
+	if (nvlhdrp->nvlh_size > SIZE_MAX - sizeof(*nvlhdrp)) {
+		ERRNO_SET(EINVAL);
+		return (false);
+	}
+
 	return (true);
 }