diff --git a/src/Controller/Admin/DataObject/ClassController.php b/src/Controller/Admin/DataObject/ClassController.php
index 2bd78f92..c5fa7a0f 100644
--- a/src/Controller/Admin/DataObject/ClassController.php
+++ b/src/Controller/Admin/DataObject/ClassController.php
@@ -1820,6 +1820,9 @@ public function getIconsAction(Request $request, EventDispatcherInterface $event
         for ($i = $startIndex; $i < $limit; $i++) {
             $icon = $icons[$i];
             $content = file_get_contents(OPENDXP_WEB_ROOT . $icon);
+            if ($content === false) {
+                continue;
+            }
             $result[] = [
                 'text' => sprintf(
                     '<img style="%s" src="data:%s;base64,%s"/>',
diff --git a/src/Controller/Admin/DataObject/QuantityValueController.php b/src/Controller/Admin/DataObject/QuantityValueController.php
index 9bd3971e..354cc1c4 100644
--- a/src/Controller/Admin/DataObject/QuantityValueController.php
+++ b/src/Controller/Admin/DataObject/QuantityValueController.php
@@ -27,6 +27,7 @@
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 use Symfony\Component\Routing\Attribute\Route;
 
 /**
@@ -46,6 +47,9 @@ public function unitImportAction(Request $request): JsonResponse
         $uploadFile = $request->files->get('Filedata');
 
         $json = file_get_contents($uploadFile->getPathname());
+        if ($json === false) {
+            throw new BadRequestHttpException('Failed to read file');
+        }
         $success = $this->service->importDefinitionFromJson($json);
         $response = $this->adminJson(['success' => $success]);
         $response->headers->set('Content-Type', 'text/html');
@@ -126,10 +130,14 @@ public function unitProxyAction(Request $request): JsonResponse
         $this->checkPermission('quantityValueUnits');
 
         if ($request->request->has('data')) {
+            $data = json_decode($request->request->get('data'), true);
+            if (!is_array($data)) {
+                throw new BadRequestHttpException('Invalid data format');
+            }
+            $id = $data['id'];
+            $unit = Unit::getById($id);
+
             if ($request->query->get('xaction') === 'destroy') {
-                $data = json_decode($request->request->get('data'), true);
-                $id = $data['id'];
-                $unit = \OpenDxp\Model\DataObject\QuantityValue\Unit::getById($id);
                 if (!empty($unit)) {
                     $unit->delete();
 
@@ -139,8 +147,6 @@ public function unitProxyAction(Request $request): JsonResponse
                 throw new Exception('Unit with id ' . $id . ' not found.');
             }
             if ($request->query->get('xaction') === 'update') {
-                $data = json_decode($request->request->get('data'), true);
-                $unit = Unit::getById($data['id']);
                 if (!empty($unit)) {
                     if (($data['baseunit'] ?? null) == -1) {
                         $data['baseunit'] = null;
@@ -151,15 +157,14 @@ public function unitProxyAction(Request $request): JsonResponse
                     return $this->adminJson(['data' => $unit->getObjectVars(), 'success' => true]);
                 }
 
-                throw new Exception('Unit with id ' . $data['id'] . ' not found.');
+                throw new Exception('Unit with id ' . $id . ' not found.');
             }
             if ($request->query->get('xaction') === 'create') {
-                $data = json_decode($request->request->get('data'), true);
                 if (isset($data['baseunit']) && $data['baseunit'] === -1) {
                     $data['baseunit'] = null;
                 }
-                $id = $data['id'];
-                if (Unit::getById($id)) {
+
+                if ($unit instanceof Unit) {
                     throw new Exception('unit with ID [' . $id . '] already exists');
                 }
                 if (mb_strlen($id) > 50) {
diff --git a/src/GDPR/DataProvider/Assets.php b/src/GDPR/DataProvider/Assets.php
index fa4fe118..9b62ecda 100644
--- a/src/GDPR/DataProvider/Assets.php
+++ b/src/GDPR/DataProvider/Assets.php
@@ -64,6 +64,9 @@ public function doExportData(Asset $asset): Response
 
         foreach (array_keys($this->exportIds) as $id) {
             $theAsset = Asset::getById((int) $id);
+            if (!$theAsset instanceof Asset) {
+                continue;
+            }
 
             $resultItem = Exporter::exportAsset($theAsset);
             $resultItem = json_encode($resultItem);
diff --git a/src/GDPR/DataProvider/DataObjects.php b/src/GDPR/DataProvider/DataObjects.php
index c34196fa..12c21771 100644
--- a/src/GDPR/DataProvider/DataObjects.php
+++ b/src/GDPR/DataProvider/DataObjects.php
@@ -62,13 +62,17 @@ public function doExportData(AbstractObject $object): array
         if (!empty($this->exportIds['object'])) {
             foreach (array_keys($this->exportIds['object']) as $id) {
                 $object = AbstractObject::getById((int)$id);
-                $exportResult[] = Exporter::exportObject($object);
+                if ($object instanceof AbstractObject) {
+                    $exportResult[] = Exporter::exportObject($object);
+                }
             }
         }
         if (!empty($this->exportIds['image'])) {
             foreach (array_keys($this->exportIds['image']) as $id) {
                 $theAsset = Asset::getById((int) $id);
-                $exportResult[] = Exporter::exportAsset($theAsset);
+                if ($theAsset instanceof Asset) {
+                    $exportResult[] = Exporter::exportAsset($theAsset);
+                }
             }
         }
 
diff --git a/src/Twig/Extension/AdminExtension.php b/src/Twig/Extension/AdminExtension.php
index a0c3c4dc..e13a8530 100644
--- a/src/Twig/Extension/AdminExtension.php
+++ b/src/Twig/Extension/AdminExtension.php
@@ -135,7 +135,14 @@ public function getLoginBackgroundImage(string $overwrite = ''): string
     #[\Twig\Attribute\AsTwigFilter('opendxp_inline_icon')]
     public function inlineIcon(string $icon): string
     {
+        if (!is_file($icon)) {
+            return '<!-- Icon file not found: ' . htmlspecialchars($icon) . ' -->';
+        }
+
         $content = file_get_contents($icon);
+        if ($content === false) {
+            return '<!-- Failed to read icon file: ' . htmlspecialchars($icon) . ' -->';
+        }
 
         return sprintf(
             '<img src="data:%s;base64,%s" title="%s" data-imgpath="%s" />',