diff --git a/src/server/game/Server/WorldSocket.cpp b/src/server/game/Server/WorldSocket.cpp
index 9e3c47caea2..24406cdbdab 100644
--- a/src/server/game/Server/WorldSocket.cpp
+++ b/src/server/game/Server/WorldSocket.cpp
@@ -733,6 +733,10 @@ int WorldSocket::ProcessIncoming(WorldPacket* new_pct)
                     return -1;
                 }
 
+                // prevent invalid memory access/crash with custom opcodes
+                if (opcode >= NUM_OPCODE_HANDLERS)
+                    return 0;
+
                 OpcodeHandler const* handler = opcodeTable[opcode];
                 if (!handler || handler->Status == STATUS_UNHANDLED)
                 {