diff --git a/client/proxusb.c b/client/proxusb.c
index 0a50b9910..15513bf0d 100644
--- a/client/proxusb.c
+++ b/client/proxusb.c
@@ -10,6 +10,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <stdbool.h>
 #include <unistd.h>
 #include <usb.h>