diff --git a/src/event.c b/src/event.c
index 39bf5507..007b10b4 100644
--- a/src/event.c
+++ b/src/event.c
@@ -1006,9 +1006,9 @@ static void handleClientMessage(XEvent * event)
 		char *command;
 		size_t len;
 
-		len = sizeof(event->xclient.data.b) + 1;
-		command = wmalloc(len);
-		strncpy(command, event->xclient.data.b, sizeof(event->xclient.data.b));
+		len = sizeof(event->xclient.data.b);
+		command = wmalloc(len + 1);
+		strncpy(command, event->xclient.data.b, len);
 
 		if (strncmp(command, "Reconfigure", sizeof("Reconfigure")) == 0) {
 			wwarning(_("Got Reconfigure command"));