diff --git a/contrib/epee/include/gzip_encoding.h b/contrib/epee/include/gzip_encoding.h
index 9cbff601..e2e1ea2c 100644
--- a/contrib/epee/include/gzip_encoding.h
+++ b/contrib/epee/include/gzip_encoding.h
@@ -224,6 +224,7 @@ namespace net_utils
   struct abstract_callback_base
   {
     virtual bool do_call(const std::string& piece_of_transfer) = 0;
+    virtual ~abstract_callback_base() {}
   };
 
   template <typename callback_t>
diff --git a/contrib/epee/include/net/http_client.h b/contrib/epee/include/net/http_client.h
index 001d7ceb..0dee38a5 100644
--- a/contrib/epee/include/net/http_client.h
+++ b/contrib/epee/include/net/http_client.h
@@ -907,6 +907,7 @@ using namespace std;
     struct idle_handler_base
     {
       virtual bool do_call(const std::string& piece_of_data, uint64_t total_bytes, uint64_t received_bytes) = 0;
+      virtual idle_handler_base() {}
     };
 
     template <typename callback_t>