diff --git a/src/cryptonote_basic/tx_extra.h b/src/cryptonote_basic/tx_extra.h
index ac3089e2e5e..5bece68110e 100755
--- a/src/cryptonote_basic/tx_extra.h
+++ b/src/cryptonote_basic/tx_extra.h
@@ -330,6 +330,13 @@ namespace cryptonote
       FIELD(m_portions)
       FIELD(m_expiration_timestamp)
       FIELD(m_master_node_signature)
+      if (Archive::is_deserializer)
+      {
+        if (m_public_spend_keys.size() != m_public_view_keys.size())
+          throw std::invalid_argument{"tx_extra_master_node_register: spend/view key count mismatch"};
+        if (m_public_spend_keys.size() != m_portions.size())
+          throw std::invalid_argument{"tx_extra_master_node_register: spend/portions count mismatch"};
+      }
     END_SERIALIZE()
   };
 
diff --git a/src/cryptonote_core/master_node_list.cpp b/src/cryptonote_core/master_node_list.cpp
index b6e90a1c8fd..9cb6ac559d7 100755
--- a/src/cryptonote_core/master_node_list.cpp
+++ b/src/cryptonote_core/master_node_list.cpp
@@ -301,6 +301,9 @@ namespace master_nodes
     if (!cryptonote::get_master_node_pubkey_from_tx_extra(tx.extra, master_node_key))
       return false;
 
+    if (registration.m_public_spend_keys.size() != registration.m_public_view_keys.size()
+        || registration.m_public_spend_keys.size() != registration.m_portions.size())
+      return false;
     contributor_args.addresses.clear();
     contributor_args.addresses.reserve(registration.m_public_spend_keys.size());
     for (size_t i = 0; i < registration.m_public_spend_keys.size(); i++) {
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index 799aca942b2..5f275cbecd0 100755
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -710,9 +710,13 @@ namespace cryptonote::rpc {
       void operator()(const tx_extra_security_signature& x) { set("security_sig", tools::type_to_hex(x.m_security_signature)); }
       void operator()(const tx_extra_master_node_register& x) {
         json reservations{};
-        for (size_t i = 0; i < x.m_portions.size(); i++)
-          reservations[get_account_address_as_str(nettype, false, {x.m_public_spend_keys[i], x.m_public_view_keys[i]})]
-            = microportion(x.m_portions[i]);
+        if (x.m_public_spend_keys.size() == x.m_public_view_keys.size()
+            && x.m_public_spend_keys.size() == x.m_portions.size())
+        {
+          for (size_t i = 0; i < x.m_portions.size(); i++)
+            reservations[get_account_address_as_str(nettype, false, {x.m_public_spend_keys[i], x.m_public_view_keys[i]})]
+              = microportion(x.m_portions[i]);
+        }
         set("mn_registration", json{
           {"fee", microportion(x.m_portions_for_operator)},
           {"expiry", x.m_expiration_timestamp},