diff -Naur x11vnc-0.9.13-ori/x11vnc/win_utils.c x11vnc-0.9.13/x11vnc/win_utils.c
--- x11vnc-0.9.13-ori/x11vnc/win_utils.c	2016-10-07 23:26:03.248600761 +0200
+++ x11vnc-0.9.13/x11vnc/win_utils.c	2016-10-07 23:26:51.919256706 +0200
@@ -262,8 +262,8 @@
 	}
 
 	last_snap = now;
-	if (num > stack_list_len + blackouts) {
-		int n = 2*num;
+	if (num + blackouts > stack_list_len) {
+		int n = 2 * (num + blackouts);
 		free(stack_list);
 		stack_list = (winattr_t *) malloc(n*sizeof(winattr_t));
 		stack_list_len = n;
diff -Naur x11vnc-0.9.13-ori/x11vnc/xrecord.c x11vnc-0.9.13/x11vnc/xrecord.c
--- x11vnc-0.9.13-ori/x11vnc/xrecord.c	2016-10-07 23:26:03.248600761 +0200
+++ x11vnc-0.9.13/x11vnc/xrecord.c	2016-10-07 23:27:49.566700470 +0200
@@ -964,7 +964,7 @@
 	data = (char *)req;
 	data += sz_xConfigureWindowReq;
 
-	for (i=0; i<req->length; i++) {
+	for (i = 0; i < req->length -  sz_xConfigureWindowReq / 4 && i < 4; i++) {
 		unsigned int v;
 		/*
 		 * We use unsigned int for the values.  There were