diff --git a/Classes/Frontend/DataProcessing/CategoriesCounts.php b/Classes/Frontend/DataProcessing/CategoriesCounts.php
index 0bffcce..dc1c4cb 100644
--- a/Classes/Frontend/DataProcessing/CategoriesCounts.php
+++ b/Classes/Frontend/DataProcessing/CategoriesCounts.php
@@ -53,8 +53,8 @@ class CategoriesCounts implements DataProcessorInterface
         }
 
         $processedData[$as] = $this->getCategoriesCount(
-            $parent,
-            $orderBy
+            (int) $parent,
+            (string) $orderBy
         );
 
         return $processedData;
diff --git a/Classes/Frontend/DataProcessing/NaturalSortingProcessor.php b/Classes/Frontend/DataProcessing/NaturalSortingProcessor.php
index b7eed5e..54bc41d 100644
--- a/Classes/Frontend/DataProcessing/NaturalSortingProcessor.php
+++ b/Classes/Frontend/DataProcessing/NaturalSortingProcessor.php
@@ -42,7 +42,14 @@ class NaturalSortingProcessor implements DataProcessorInterface
         array $processedData
     ) {
         $variablePath = $cObj->stdWrapValue('variablePath', $processorConfiguration, '');
+        if (is_string($variablePath) === false) {
+            throw new \Exception('Variable path needs to be string.', 1663760889);
+        }
+
         $variableSubPath = $cObj->stdWrapValue('variableSubPath', $processorConfiguration, '');
+        if (is_string($variableSubPath) === false) {
+            throw new \Exception('Variable Sub Path needs to be string.', 1663760908);
+        }
 
         if ($variablePath === '' || $variableSubPath === '') {
             throw new \Exception('Provide variablePath as well as variableSubPath.', 1638373263);
diff --git a/Classes/Frontend/RssFeed/XmlSitemapRenderer.php b/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
index dd65e46..9c96d09 100644
--- a/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
+++ b/Classes/Frontend/RssFeed/XmlSitemapRenderer.php
@@ -41,7 +41,7 @@ class XmlSitemapRenderer extends Typo3XmlSitemapRenderer
         return parent::render($_, $typoScriptConfiguration, $request);
     }
 
-    protected function initialize(array $fullConfiguration)
+    protected function initialize(array $fullConfiguration): void
     {
         parent::initialize($fullConfiguration);
         $this->view->assign('settings', $this->getSettings());
@@ -51,7 +51,7 @@ class XmlSitemapRenderer extends Typo3XmlSitemapRenderer
     {
         $settings = [];
         foreach (array_keys($this->typoScriptConfiguration['userFunc.']['variables.'] ?? []) as $variableName) {
-            if (substr($variableName, -1) === '.') {
+            if (!is_string($variableName) || substr($variableName, -1) === '.') {
                 continue;
             }
             $settings[$variableName] = $this->cObj->cObjGetSingle(
diff --git a/Classes/Hooks/Backend/PageLayoutHeader.php b/Classes/Hooks/Backend/PageLayoutHeader.php
index 33cbae2..c5cc2ae 100644
--- a/Classes/Hooks/Backend/PageLayoutHeader.php
+++ b/Classes/Hooks/Backend/PageLayoutHeader.php
@@ -31,14 +31,15 @@ class PageLayoutHeader
     /**
      * @var array
      */
-    private $pageinfo;
+    private $pageinfo = [];
 
     public function render(
         array $params,
         PageLayoutController $pageLayoutController
     ): string {
-        // @extensionScannerIgnoreLine At least in v10 this is a false positive
-        $this->pageinfo = $pageLayoutController->pageinfo;
+        if (is_array($pageLayoutController->pageinfo)) {
+            $this->pageinfo = $pageLayoutController->pageinfo;
+        }
 
         // TODO: Check whether two levels up is uid 2, which holds all blog posts
         // To prevent rendering on non blog posts
@@ -50,25 +51,25 @@ class PageLayoutHeader
             'metaInfo' => [
                 [
                     'label' => 'meta-description',
-                    'value' => $this->pageinfo['description'],
+                    'value' => $this->pageinfo['description'] ?? '',
                     'field' => 'description',
                     'type' => 'string',
                 ],
                 [
                     'label' => 'introduction',
-                    'value' => $this->pageinfo['abstract'],
+                    'value' => $this->pageinfo['abstract'] ?? '',
                     'field' => 'abstract',
                     'type' => 'string',
                 ],
                 [
                     'label' => 'published',
-                    'value' => $this->pageinfo['lastUpdated'],
+                    'value' => $this->pageinfo['lastUpdated'] ?? '',
                     'field' => 'lastUpdated',
                     'type' => 'date',
                 ],
                 [
                     'label' => 'updated',
-                    'value' => $this->pageinfo['SYS_LASTCHANGED'],
+                    'value' => $this->pageinfo['SYS_LASTCHANGED'] ?? '',
                     'type' => 'date',
                 ],
                 [
@@ -91,7 +92,7 @@ class PageLayoutHeader
 
     private function resolvePageMedia(): array
     {
-        $page = ['uid' => $this->pageinfo['uid']];
+        $page = ['uid' => $this->pageinfo['uid'] ?? ''];
         $files = new FileCollector();
         $files->addFilesFromRelation('pages', 'media', $page);
 
diff --git a/Classes/UserFunction/CodeHighlighting.php b/Classes/UserFunction/CodeHighlighting.php
index 545cc37..ba38eea 100644
--- a/Classes/UserFunction/CodeHighlighting.php
+++ b/Classes/UserFunction/CodeHighlighting.php
@@ -46,7 +46,7 @@ class CodeHighlighting
             // Highlight some code.
             $highlighted = $highlighter->highlightAuto($code);
             $content = '<pre><code>' . $highlighted->value . '</code></pre>';
-        } catch (DomainException $e) {
+        } catch (\DomainException $e) {
             $content = '<pre><code>' . $code . '</code></pre>';
         }
 
diff --git a/Classes/ViewHelpers/Format/IdViewHelper.php b/Classes/ViewHelpers/Format/IdViewHelper.php
index ee7deb6..0deeeab 100644
--- a/Classes/ViewHelpers/Format/IdViewHelper.php
+++ b/Classes/ViewHelpers/Format/IdViewHelper.php
@@ -35,7 +35,7 @@ class IdViewHelper extends AbstractViewHelper
 {
     use CompileWithContentArgumentAndRenderStatic;
 
-    public function initializeArguments()
+    public function initializeArguments(): void
     {
         $this->registerArgument('value', 'string', 'string to format');
     }
@@ -51,7 +51,7 @@ class IdViewHelper extends AbstractViewHelper
         }
         $value = (string)$value;
         $value = str_replace(' ', '_', $value);
-        $value = preg_replace('#\W#', '', $value);
+        $value = preg_replace('#\W#', '', $value) ?? '';
         $value = GeneralUtility::underscoredToUpperCamelCase($value);
         $value = lcfirst($value);
         return $value;
diff --git a/Configuration/TCA/Overrides/pages.php b/Configuration/TCA/Overrides/pages.php
index 057b120..8190331 100644
--- a/Configuration/TCA/Overrides/pages.php
+++ b/Configuration/TCA/Overrides/pages.php
@@ -40,7 +40,7 @@
     \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes(
         $tableName,
         'rel',
-        \TYPO3\CMS\Core\Domain\Repository\PageRepository::DOKTYPE_LINK,
+        (string) \TYPO3\CMS\Core\Domain\Repository\PageRepository::DOKTYPE_LINK,
         'after:url'
     );