diff --git a/capinfos.c b/capinfos.c
index 2261e7e6e1..f36e07a633 100644
--- a/capinfos.c
+++ b/capinfos.c
@@ -1107,6 +1107,7 @@ process_cap_file(wtap *wth, const char *filename)
 
   cf_info.num_interfaces = idb_info->interface_data->len;
   cf_info.interface_packet_counts  = g_array_sized_new(FALSE, TRUE, sizeof(guint32), cf_info.num_interfaces);
+  g_array_set_size(cf_info.interface_packet_counts, cf_info.num_interfaces);
   cf_info.pkt_interface_id_unknown = 0;
 
   g_free(idb_info);