diff --git a/src/network/protocols/game_protocol.cpp b/src/network/protocols/game_protocol.cpp
index e81da7f0e..dd379a06c 100644
--- a/src/network/protocols/game_protocol.cpp
+++ b/src/network/protocols/game_protocol.cpp
@@ -184,7 +184,13 @@ void GameProtocol::handleControllerAction(Event *event)
             //rewind_delta = not_rewound - cur_ticks;
         }
         uint8_t kart_id = data.getUInt8();
-        assert(kart_id < World::getWorld()->getNumKarts());
+        if (NetworkConfig::get()->isServer() &&
+            !event->getPeer()->availableKartID(kart_id))
+        {
+            Log::warn("GameProtocol", "Wrong kart id %d from %s.",
+                kart_id, event->getPeer()->getAddress().toString().c_str());
+            return;
+        }
 
         PlayerAction action = (PlayerAction)(data.getUInt8());
         int value   = data.getUInt32();
diff --git a/src/network/protocols/server_lobby.cpp b/src/network/protocols/server_lobby.cpp
index 40e3c0a3e..7444d4e5b 100644
--- a/src/network/protocols/server_lobby.cpp
+++ b/src/network/protocols/server_lobby.cpp
@@ -496,13 +496,17 @@ void ServerLobby::asynchronousUpdate()
             m_game_setup->sortPlayersForGrandPrix();
             m_game_setup->sortPlayersForTeamGame();
             auto players = m_game_setup->getConnectedPlayers();
+            for (auto& player : players)
+                player->getPeer()->clearAvailableKartIDs();
             NetworkString* load_world = getNetworkString();
             load_world->setSynchronous(true);
             load_world->addUInt8(LE_LOAD_WORLD).encodeString(std::get<0>(result))
                 .addUInt8(std::get<1>(result)).addUInt8(std::get<2>(result))
                 .addUInt8((uint8_t)players.size());
-            for (auto player : players)
+            for (unsigned i = 0; i < players.size(); i++)
             {
+                std::shared_ptr<NetworkPlayerProfile>& player = players[i];
+                player->getPeer()->addAvailableKartID(i);
                 load_world->encodeString(player->getName())
                     .addUInt32(player->getHostId())
                     .addFloat(player->getDefaultKartColor())
diff --git a/src/network/stk_peer.hpp b/src/network/stk_peer.hpp
index fbf6c45f4..a6b931ef3 100644
--- a/src/network/stk_peer.hpp
+++ b/src/network/stk_peer.hpp
@@ -89,6 +89,8 @@ protected:
 
     std::atomic<uint32_t> m_average_ping;
 
+    std::set<unsigned> m_available_kart_ids;
+
 public:
     STKPeer(ENetPeer *enet_peer, STKHost* host, uint32_t host_id);
     // ------------------------------------------------------------------------
@@ -181,6 +183,13 @@ public:
     bool isWaitingForGame() const         { return m_waiting_for_game.load(); }
     // ------------------------------------------------------------------------
     bool isDisconnected() const               { return m_disconnected.load(); }
+    // ------------------------------------------------------------------------
+    void clearAvailableKartIDs() { m_available_kart_ids.clear(); }
+    // ------------------------------------------------------------------------
+    void addAvailableKartID(unsigned id)   { m_available_kart_ids.insert(id); }
+    // ------------------------------------------------------------------------
+    bool availableKartID(unsigned id)
+        { return m_available_kart_ids.find(id) != m_available_kart_ids.end(); }
 };   // STKPeer
 
 #endif // STK_PEER_HPP