--- a/Classes/Controller/FeuserController.php
+++ b/Classes/Controller/FeuserController.php
@@ -106,6 +106,9 @@
         return false;
     }

+    /**
+    * @throws Exception
+    */
     protected function initializeActionMethodValidators(): void
     {
         $this->settings['hasOriginalRequest'] = $this->request->getAttribute('extbase')->getOriginalRequest() !== null;
@@ -116,6 +119,9 @@
         if (!is_array($this->settings['fields']['selected'])) {
             $this->settings['fields']['selected'] = [];
         }
+        if (in_array('usergroup', $this->settings['fields']['selected'])) {
+            throw new Exception('Selecting "usergroup" in frontend isn\'t supported.');
+        }

         if ($this->actionIsIgnored() || $this->skipValidation()) {
             parent::initializeActionMethodValidators();
@@ -305,10 +311,8 @@
             $configuration = GeneralUtility::makeInstance(PropertyMappingConfiguration::class);
         }

-        $configuration->allowAllProperties();
-        $configuration->forProperty('usergroup')->allowAllProperties();
-        $configuration->forProperty('moduleSysDmailCategory')->allowAllProperties();
-        $configuration->forProperty('image')->allowAllProperties();
+        $configuration->allowProperties(...($this->settings['fields']['selected'] ?? []));
+
         $configuration->setTypeConverterOption(
             PersistentObjectConverter::class,
             (string)PersistentObjectConverter::CONFIGURATION_CREATION_ALLOWED,