diff --git a/server/src/core/idobject.cpp b/server/src/core/idobject.cpp
index b7fe6316..c0b389e4 100644
--- a/server/src/core/idobject.cpp
+++ b/server/src/core/idobject.cpp
@@ -1,7 +1,7 @@
 /**
- * Traintastic
+ * server/src/core/idobject.cpp
  *
- * Copyright (C) 2019-2022 Reinder Feenstra
+ * Copyright (C) 2019-2023 Reinder Feenstra
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -22,6 +22,7 @@
 #include "../traintastic/traintastic.hpp"
 #include "../world/getworld.hpp"
 #include "attributes.hpp"
+#include "isvalidobjectid.hpp"
 #include "../utils/displayname.hpp"
 
 IdObject::IdObject(World& world, std::string_view _id) :
@@ -33,6 +34,8 @@ IdObject::IdObject(World& world, std::string_view _id) :
     },
     [this](std::string& value)
     {
+      if(!isValidObjectId(value))
+        throw invalid_value_error();
       auto& m = m_world.m_objects;
       if(m.find(value) != m.end())
         return false;
diff --git a/server/src/core/isvalidobjectid.cpp b/server/src/core/isvalidobjectid.cpp
new file mode 100644
index 00000000..77539b7d
--- /dev/null
+++ b/server/src/core/isvalidobjectid.cpp
@@ -0,0 +1,30 @@
+/**
+ * server/src/core/isvalidobjectid.cpp
+ *
+ * This file is part of the traintastic source code.
+ *
+ * Copyright (C) 2023 Reinder Feenstra
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include "isvalidobjectid.hpp"
+#include <regex>
+
+bool isValidObjectId(std::string_view id)
+{
+  static const std::regex re{"[a-z][a-z0-9_]*", };
+  return std::regex_match(id.begin(), id.end(), re);
+}
diff --git a/server/src/core/isvalidobjectid.hpp b/server/src/core/isvalidobjectid.hpp
new file mode 100644
index 00000000..b588adb1
--- /dev/null
+++ b/server/src/core/isvalidobjectid.hpp
@@ -0,0 +1,30 @@
+/**
+ * server/src/core/isvalidobjectid.hpp
+ *
+ * This file is part of the traintastic source code.
+ *
+ * Copyright (C) 2023 Reinder Feenstra
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef TRAINTASTIC_SERVER_CORE_ISVALIDOBJECTID_HPP
+#define TRAINTASTIC_SERVER_CORE_ISVALIDOBJECTID_HPP
+
+#include <string_view>
+
+bool isValidObjectId(std::string_view id);
+
+#endif
diff --git a/server/src/world/worldloader.cpp b/server/src/world/worldloader.cpp
index 060294d5..8d21a1a8 100644
--- a/server/src/world/worldloader.cpp
+++ b/server/src/world/worldloader.cpp
@@ -3,7 +3,7 @@
  *
  * This file is part of the traintastic source code.
  *
- * Copyright (C) 2019-2022 Reinder Feenstra
+ * Copyright (C) 2019-2023 Reinder Feenstra
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -26,6 +26,7 @@
 #include <boost/uuid/string_generator.hpp>
 #include <boost/uuid/uuid_io.hpp>
 #include "world.hpp"
+#include "../core/isvalidobjectid.hpp"
 #include "../utils/startswith.hpp"
 #include "../utils/stripsuffix.hpp"
 #include "ctwreader.hpp"
@@ -167,7 +168,12 @@ void WorldLoader::load()
   for(json object : data["objects"])
   {
     if(auto it = object.find("id"); it != object.end())
-      m_objects.insert({it.value().get<std::string>(), {object, nullptr, false}});
+    {
+      auto id = it.value().get<std::string>();
+      if(!isValidObjectId(id))
+        throw std::runtime_error("invalid object id value");
+      m_objects.insert({std::move(id), {object, nullptr, false}});
+    }
     else
       throw std::runtime_error("id missing");
   }