diff --git a/vpnor/backend.h b/vpnor/backend.h
index 010223842fd50b9fd5168119aa230d4bc9fd0d38..949e5c1fd4b26209711d1eaf0dfcda05f455ea19 100644
--- a/vpnor/backend.h
+++ b/vpnor/backend.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include <limits.h>
+#include <string.h>
 
 struct mbox_context;
 struct vpnor_partition_table;