1 files changed, 7 insertions, 1 deletions
diff --git a/modules/enet/networked_multiplayer_enet.cpp b/modules/enet/networked_multiplayer_enet.cpp
index e53846e269..000917507a 100644
--- a/modules/enet/networked_multiplayer_enet.cpp
+++ b/modules/enet/networked_multiplayer_enet.cpp
@@ -231,6 +231,13 @@ void NetworkedMultiplayerENet::poll() {
 					break;
 				}
 
+				// A client joined with an invalid ID (neagtive values, 0, and 1 are reserved).
+				// Probably trying to exploit us.
+				if (server && ((int)event.data < 2 || peer_map.has((int)event.data))) {
+					enet_peer_reset(event.peer);
+					ERR_CONTINUE(true);
+				}
+
 				int *new_id = memnew(int);
 				*new_id = event.data;
 
@@ -426,7 +433,6 @@ bool NetworkedMultiplayerENet::is_server() const {
 void NetworkedMultiplayerENet::close_connection(uint32_t wait_usec) {
 
 	ERR_FAIL_COND(!active);
-	ERR_FAIL_COND(wait_usec < 0);
 
 	_pop_current_packet();