See also https://github.com/octo/liboping/issues/72

Index: src/oping.c
--- src/oping.c.orig
+++ src/oping.c
@@ -1125,7 +1125,7 @@ static int update_graph_prettyping (ping_context_t *ct
 			wattron (ctx->window, COLOR_PAIR(color));
 
 		if (has_utf8())
-			mvwprintw (ctx->window, /* y = */ 3, /* x = */ x + 2, symbol);
+			mvwprintw (ctx->window, /* y = */ 3, /* x = */ x + 2, "%s", symbol);
 		else
 			mvwaddch (ctx->window, /* y = */ 3, /* x = */ x + 2, symbolc);
 
@@ -1222,7 +1222,7 @@ static int update_graph_histogram (ping_context_t *ctx
 		if (counters[x] == 0)
 			mvwaddch (ctx->window, /* y = */ 3, /* x = */ x + 2, ' ');
 		else if (has_utf8 ())
-			mvwprintw (ctx->window, /* y = */ 3, /* x = */ x + 2,
+			mvwprintw (ctx->window, /* y = */ 3, /* x = */ x + 2, "%s",
 					hist_symbols_utf8[index]);
 		else
 			mvwaddch (ctx->window, /* y = */ 3, /* x = */ x + 2,
@@ -1598,7 +1598,7 @@ static void update_host_hook (pingobj_iter_t *iter, /*
 			else
 				color = OPING_RED;
 
-			HOST_PRINTF ("%zu bytes from %s (%s): icmp_seq=%u ttl=%i ",
+			HOST_PRINTF ("%zu bytes from %s (%s): icmp_seq=%u ttl=%i %s",
 					data_len, context->host, context->addr,
 					sequence, recv_ttl,
 					format_qos (recv_qos, recv_qos_str, sizeof (recv_qos_str)));