diff --git a/dap-sdk b/dap-sdk
index a620492c6b5908345c55167618ab2802431cfdb9..e03e59dbf5f4c00d2232c43e3aa1ecd51b7f3622 160000
--- a/dap-sdk
+++ b/dap-sdk
@@ -1 +1 @@
-Subproject commit a620492c6b5908345c55167618ab2802431cfdb9
+Subproject commit e03e59dbf5f4c00d2232c43e3aa1ecd51b7f3622
diff --git a/modules/consensus/esbocs/dap_chain_cs_esbocs.c b/modules/consensus/esbocs/dap_chain_cs_esbocs.c
index f9471f2ab185ec72cd31ce275c90de9de71448b1..224b427fef553f65e348f726826936cc8ab4e924 100644
--- a/modules/consensus/esbocs/dap_chain_cs_esbocs.c
+++ b/modules/consensus/esbocs/dap_chain_cs_esbocs.c
@@ -1087,6 +1087,10 @@ static void s_message_chain_add(dap_chain_esbocs_session_t *a_session,
                                 dap_chain_hash_fast_t *a_message_hash,
                                 dap_chain_addr_t *a_signing_addr)
 {
+    if (NULL == a_message) {
+        log_it(L_ERROR, "Argument is NULL for s_message_chain_add");
+        return;
+    }
     dap_chain_esbocs_round_t *l_round = &a_session->cur_round;
     dap_chain_esbocs_message_item_t *l_message_item = DAP_NEW_Z(dap_chain_esbocs_message_item_t);
     if (!a_message_hash) {
@@ -1134,6 +1138,10 @@ static void s_session_candidate_submit(dap_chain_esbocs_session_t *a_session)
 static void s_session_candidate_verify(dap_chain_esbocs_session_t *a_session, dap_chain_block_t *a_candidate,
                                        size_t a_candidate_size, dap_hash_fast_t *a_candidate_hash)
 {
+    if (NULL == a_candidate) {
+        log_it(L_ERROR, "Argument is NULL for s_session_candidate_verify");
+        return;
+    }
     // Process early received messages
     for (dap_chain_esbocs_message_item_t *l_item = a_session->cur_round.message_items; l_item; l_item = l_item->hh.next) {
         if (l_item->unprocessed &&
@@ -1177,6 +1185,10 @@ static void s_session_candidate_verify(dap_chain_esbocs_session_t *a_session, da
 
 static void s_session_candidate_precommit(dap_chain_esbocs_session_t *a_session, dap_chain_esbocs_message_t *a_message)
 {
+    if (NULL == a_message) {
+        log_it(L_ERROR, "Argument is NULL for s_session_candidate_precommit");
+        return;
+    }
     bool l_cs_debug = PVT(a_session->esbocs)->debug;
     uint16_t l_cs_level = PVT(a_session->esbocs)->min_validators_count;
     byte_t *l_message_data = a_message->msg_n_sign;
@@ -1240,6 +1252,10 @@ static void s_session_candidate_precommit(dap_chain_esbocs_session_t *a_session,
 static bool s_session_candidate_to_chain(dap_chain_esbocs_session_t *a_session, dap_chain_hash_fast_t *a_candidate_hash,
                                          dap_chain_block_t *a_candidate, size_t a_candidate_size)
 {
+    if (NULL == a_candidate) {
+        log_it(L_ERROR, "Argument is NULL for s_session_candidate_to_chain");
+        return false;
+    }
     bool res = false;
     dap_chain_block_t *l_candidate = DAP_DUP_SIZE(a_candidate, a_candidate_size);
     dap_chain_atom_verify_res_t l_res = a_session->chain->callback_atom_add(a_session->chain, l_candidate, a_candidate_size);
diff --git a/modules/consensus/none/dap_chain_cs_none.c b/modules/consensus/none/dap_chain_cs_none.c
index 608ea742ffe1cd4c9cc7cc9ece14dc0e1858a2dd..8b7937825c51a1b6aa7e7e8134ccaa38b37045bb 100644
--- a/modules/consensus/none/dap_chain_cs_none.c
+++ b/modules/consensus/none/dap_chain_cs_none.c
@@ -239,7 +239,8 @@ void dap_chain_gdb_delete(dap_chain_t * a_chain)
     DAP_DELETE(l_gdb_priv->group_datums);
 
     DAP_DELETE(l_gdb);
-    a_chain->_inheritor = NULL;
+    if (a_chain)
+        a_chain->_inheritor = NULL;
 }
 
 /**
@@ -360,6 +361,10 @@ static size_t s_chain_callback_datums_pool_proc(dap_chain_t * a_chain, dap_chain
  */
 static dap_chain_atom_verify_res_t s_chain_callback_atom_add(dap_chain_t * a_chain, dap_chain_atom_ptr_t a_atom, size_t a_atom_size)
 {
+    if (NULL == a_chain) {
+        log_it(L_WARNING, "Arguments is NULL for s_chain_callback_atom_add");
+        return ATOM_REJECT;
+    }
     dap_chain_gdb_t * l_gdb = DAP_CHAIN_GDB(a_chain);
     dap_chain_gdb_private_t *l_gdb_priv = PVT(l_gdb);
     dap_chain_datum_t *l_datum = (dap_chain_datum_t*) a_atom;
diff --git a/modules/net/dap_chain_net.c b/modules/net/dap_chain_net.c
index 81229ae1a2313b649130d8ceacddf5d5e5516058..2b7829a57e0ba2838e5f660a42ce71fd4141bc2d 100644
--- a/modules/net/dap_chain_net.c
+++ b/modules/net/dap_chain_net.c
@@ -556,8 +556,10 @@ static bool s_net_send_atoms(dap_proc_thread_t *a_thread, void *a_arg)
  */
 static void s_chain_callback_notify(void *a_arg, dap_chain_t *a_chain, dap_chain_cell_id_t a_id, void* a_atom, size_t a_atom_size)
 {
-    if (!a_arg)
+    if (!a_arg || !a_chain) {
+        log_it(L_ERROR, "Argument is NULL for s_chain_callback_notify");
         return;
+    }
     dap_chain_net_t *l_net = (dap_chain_net_t *)a_arg;
     if (!HASH_COUNT(PVT(l_net)->downlinks))
         return;
diff --git a/modules/net/srv/dap_chain_net_srv_order.c b/modules/net/srv/dap_chain_net_srv_order.c
index 43d6a4b0b644ad928e51076671cc3330cea61edb..c69291a663bc974c62a92787cef8a47eac1b7cf8 100644
--- a/modules/net/srv/dap_chain_net_srv_order.c
+++ b/modules/net/srv/dap_chain_net_srv_order.c
@@ -356,6 +356,10 @@ char *dap_chain_net_srv_order_save(dap_chain_net_t *a_net, dap_chain_net_srv_ord
 
 dap_chain_net_srv_order_t *dap_chain_net_srv_order_read(byte_t *a_order, size_t a_order_size)
 {
+    if (NULL == a_order) {
+        log_it(L_ERROR, "Argumets are NULL for dap_chain_net_srv_order_read");
+        return NULL;
+    }
     dap_chain_net_srv_order_t *l_order = (dap_chain_net_srv_order_t *)a_order;
     size_t l_order_size = dap_chain_net_srv_order_get_size((dap_chain_net_srv_order_t *)a_order);
     if (l_order->version > 3 || l_order->direction > SERV_DIR_SELL || l_order_size != a_order_size)
diff --git a/modules/service/vpn/dap_chain_net_vpn_client_tun.c b/modules/service/vpn/dap_chain_net_vpn_client_tun.c
index 801422a282b49dca80c6d51f57f8927bb0e0714b..f75fbb914cebbe6b9180f5bcd02c7db224106b8e 100644
--- a/modules/service/vpn/dap_chain_net_vpn_client_tun.c
+++ b/modules/service/vpn/dap_chain_net_vpn_client_tun.c
@@ -638,7 +638,7 @@ static void ch_sf_pkt_send(dap_stream_ch_t * a_ch, void * a_data, size_t a_data_
     //       ,inet_ntoa(in_daddr), read_ret);
     if(!a_ch) {
         log_it(L_ERROR, "Try to send to NULL channel");
-//        return;
+       return;
     }
     l_pkt_out = DAP_NEW_SIZE(ch_vpn_pkt_t, l_pkt_out_size);
     memset(&l_pkt_out->header,0,sizeof(l_pkt_out->header));
diff --git a/modules/type/dag/dap_chain_cs_dag.c b/modules/type/dag/dap_chain_cs_dag.c
index dffba69ad8fdccfdca9b5aaf69a36d5d0bb050be..0a18e641b0f0145b3b5f00bbdf9a7b4a13294d51 100644
--- a/modules/type/dag/dap_chain_cs_dag.c
+++ b/modules/type/dag/dap_chain_cs_dag.c
@@ -616,8 +616,10 @@ static size_t s_callback_add_datums(dap_chain_t *a_chain, dap_chain_datum_t **a_
 }
 
 static bool s_chain_callback_datums_pool_proc(dap_chain_t *a_chain, dap_chain_datum_t *a_datum) {
-    if (!a_datum || !a_chain)
-        log_it(L_ERROR, "Datum or chain in mempool processing comes NULL");
+    if (!a_datum || !a_chain){
+        log_it(L_ERROR, "Datum or chain in mempool processing comes NULL in s_chain_callback_datums_pool_proc");
+        return false;
+    }
 
     dap_chain_cs_dag_t * l_dag = DAP_CHAIN_CS_DAG(a_chain);
     /* If datum passes thru rounds, let's check if it wasn't added before */