diff --git a/src/Model/Table/SettingsTable.php b/src/Model/Table/SettingsTable.php
index 7fe18ac..2eb941c 100644
--- a/src/Model/Table/SettingsTable.php
+++ b/src/Model/Table/SettingsTable.php
@@ -3,6 +3,7 @@ namespace App\Model\Table;
 
 use App\Model\Table\AppTable;
 use Cake\ORM\Table;
+use Cake\Filesystem\File;
 use Cake\Core\Configure;
 use Cake\Error\Debugger;
 
@@ -73,10 +74,18 @@ class SettingsTable extends AppTable
             }
         }
         $setting['value'] = $value ?? '';
+        if (isset($setting['test'])) {
+            $validationResult = $this->SettingsProvider->evaluateFunctionForSetting($setting['test'], $setting);
+            if ($validationResult !== true) {
+                $errors[] = $validationResult;
+                $setting['errorMessage'] = $validationResult;
+            }
+        }
         if (empty($errors) && !empty($setting['beforeSave'])) {
             $beforeSaveResult = $this->SettingsProvider->evaluateFunctionForSetting($setting['beforeSave'], $setting);
             if ($beforeSaveResult !== true) {
                 $errors[] = $beforeSaveResult;
+                $setting['errorMessage'] = $validationResult;
             }
         }
         if (empty($errors)) {
@@ -85,6 +94,8 @@ class SettingsTable extends AppTable
                 if (!empty($setting['afterSave'])) {
                     $this->SettingsProvider->evaluateFunctionForSetting($setting['afterSave'], $setting);
                 }
+            } else {
+                $errors[] = __('Could not save settings on disk');
             }
         }
         return $errors;
@@ -129,8 +140,16 @@ class SettingsTable extends AppTable
         $settings = $this->readSettings();
         $settings[$name] = $value;
         $settings = json_encode($settings, JSON_PRETTY_PRINT);
-        file_put_contents(CONFIG . 'config.json', $settings);
-        $this->loadSettings();
-        return true;
+        $path = CONFIG . 'config.json';
+        $file = new File($path);
+        if ($file->writable()) {
+            $success = file_put_contents($path, $settings);
+            if ($success) {
+                $this->loadSettings();
+            }
+        } else {
+            $success = false;
+        }
+        return $success;
     }
 }
diff --git a/src/Model/Table/UserSettingsTable.php b/src/Model/Table/UserSettingsTable.php
index bdfe535..cc4b5db 100644
--- a/src/Model/Table/UserSettingsTable.php
+++ b/src/Model/Table/UserSettingsTable.php
@@ -135,4 +135,18 @@ class UserSettingsTable extends AppTable
         }
         return $result;
     }
+
+    /**
+     * validURI - Ensure the provided URI can be safely put as a link
+     *
+     * @param String $uri
+     * @return bool if the URI is safe to be put as a link
+     */
+    public function validURI(String $uri): bool
+    {
+        $parsed = parse_url($uri);
+        $isLocalPath = empty($parsed['scheme']) && empty($parsed['domain']) && !empty($parsed['path']);
+        $isValidURL = !empty($parsed['scheme']) && in_array($parsed['scheme'], ['http', 'https']) && filter_var($uri, FILTER_SANITIZE_URL);
+        return $isLocalPath || $isValidURL;
+    }
 }
diff --git a/templates/Instance/home.php b/templates/Instance/home.php
index 6d91266..e5803c2 100644
--- a/templates/Instance/home.php
+++ b/templates/Instance/home.php
@@ -1,5 +1,9 @@
 <?php
+
+use Cake\ORM\TableRegistry;
+
 $bookmarks = !empty($loggedUser->user_settings_by_name['ui.bookmarks']['value']) ? json_decode($loggedUser->user_settings_by_name['ui.bookmarks']['value'], true) : [];
+$this->userSettingsTable = TableRegistry::getTableLocator()->get('UserSettings');
 ?>
 
 <h3>
@@ -9,18 +13,24 @@ $bookmarks = !empty($loggedUser->user_settings_by_name['ui.bookmarks']['value'])
     <?= __('Bookmarks') ?>
 </h3>
 <div class="row">
-    <?php if (!empty($bookmarks)): ?>
+    <?php if (!empty($bookmarks)) : ?>
         <ul class="col-sm-12 col-md-10 col-l-8 col-xl-8 mb-3">
             <?php foreach ($bookmarks as $bookmark) : ?>
                 <li class="list-group-item">
-                    <a href="<?= h($bookmark['url']) ?>" class="w-bold">
-                        <?= h($bookmark['label']) ?>
-                    </a>
+                    <?php if ($this->userSettingsTable->validURI($bookmark['url'])): ?>
+                        <a href="<?= h($bookmark['url']) ?>" class="w-bold">
+                            <?= h($bookmark['label']) ?>
+                        </a>
+                    <?php else: ?>
+                        <span class="w-bold">
+                            <?= h($bookmark['url']) ?>
+                        </span>
+                    <?php endif; ?>
                     <span class="ms-3 fw-light"><?= h($bookmark['name']) ?></span>
                 </li>
             <?php endforeach; ?>
         </ul>
-    <?php else: ?>
+    <?php else : ?>
         <p class="fw-light"><?= __('No bookmarks') ?></p>
     <?php endif; ?>
 </div>
diff --git a/templates/UserSettings/delete_bookmark.php b/templates/UserSettings/delete_my_bookmark.php
similarity index 100%
rename from templates/UserSettings/delete_bookmark.php
rename to templates/UserSettings/delete_my_bookmark.php
diff --git a/templates/UserSettings/save_bookmark.php b/templates/UserSettings/save_my_bookmark.php
similarity index 100%
rename from templates/UserSettings/save_bookmark.php
rename to templates/UserSettings/save_my_bookmark.php
diff --git a/templates/UserSettings/set_setting.php b/templates/UserSettings/set_my_setting.php
similarity index 100%
rename from templates/UserSettings/set_setting.php
rename to templates/UserSettings/set_my_setting.php
diff --git a/templates/element/Settings/field.php b/templates/element/Settings/field.php
index 34bdde8..d52bc14 100644
--- a/templates/element/Settings/field.php
+++ b/templates/element/Settings/field.php
@@ -13,11 +13,11 @@
                         (!empty($setting['error']) ? $appView->get('variantFromSeverity')[$setting['severity']] : ''),
                     ],
                     ($setting['type'] == 'textarea' ? '' : 'type') => ($setting['type'] == 'textarea' ? '' : 'text'),
-                    'id' => $settingId,
-                    'data-setting-name' => $settingName,
-                    'value' => isset($setting['value']) ? $setting['value'] : "",
-                    'placeholder' => $setting['default'] ?? '',
-                    'aria-describedby' => "{$settingId}Help"
+                    'id' => h($settingId),
+                    'data-setting-name' => h($settingName),
+                    'value' => isset($setting['value']) ? h($setting['value']) : "",
+                    'placeholder' => empty($setting['default']) ? '' : h($setting['default']),
+                    'aria-describedby' => h("{$settingId}Help")
                 ]
             );
         })($settingName, $setting, $this);
@@ -28,13 +28,13 @@
             return $this->Bootstrap->switch([
                 'label' => h($setting['description']),
                 'checked' => !empty($setting['value']),
-                'id' => $settingId,
+                'id' => h($settingId),
                 'class' => [
                     (!empty($setting['error']) ? 'is-invalid' : ''),
                     (!empty($setting['error']) ? $appView->get('variantFromSeverity')[$setting['severity']] : ''),
                 ],
                 'attrs' => [
-                    'data-setting-name' => $settingName
+                    'data-setting-name' => h($settingName)
                 ]
             ]);
         })($settingName, $setting, $this);
@@ -53,16 +53,16 @@
                 'type' => 'number',
                 'min' => '0',
                 'step' => 1,
-                'id' => $settingId,
-                'data-setting-name' => $settingName,
-                'aria-describedby' => "{$settingId}Help"
+                'id' => h($settingId),
+                'data-setting-name' => h($settingName),
+                'aria-describedby' => h("{$settingId}Help")
             ]);
         })($settingName, $setting, $this);
 
     } elseif ($setting['type'] == 'select' || $setting['type'] == 'multi-select') {
         $input = (function ($settingName, $setting, $appView) {
             $settingId = str_replace('.', '_', $settingName);
-            $setting['value'] = $setting['value'] ?? '';
+            $setting['value'] = empty($setting['value']) ? '' : h($setting['value']);
             if ($setting['type'] == 'multi-select') {
                 if (!is_array($setting['value'])) {
                     $firstChar = substr($setting['value'], 0, 1);
@@ -77,7 +77,7 @@
             foreach ($setting['options'] as $key => $value) {
                 $optionParam = [
                     'class' => [],
-                    'value' => $key,
+                    'value' => h($key),
                 ];
                 if ($setting['type'] == 'multi-select') {
                     if (in_array($key, $setting['value'])) {
@@ -100,10 +100,10 @@
                     (!empty($setting['error']) ? $appView->get('variantFromSeverity')[$setting['severity']] : ''),
                 ],
                 ($setting['type'] == 'multi-select' ? 'multiple' : '') => ($setting['type'] == 'multi-select' ? 'multiple' : ''),
-                'id' => $settingId,
-                'data-setting-name' => $settingName,
-                'placeholder' => $setting['default'] ?? '',
-                'aria-describedby' => "{$settingId}Help"
+                'id' => h($settingId),
+                'data-setting-name' => h($settingName),
+                'placeholder' => empty($setting['default']) ? '' : h($setting['default']),
+                'aria-describedby' => h("{$settingId}Help")
             ], $options);
         })($settingName, $setting, $this);
     }
diff --git a/templates/element/layouts/sidebar/bookmark-entry.php b/templates/element/layouts/sidebar/bookmark-entry.php
index f2d01c1..a33ffe4 100644
--- a/templates/element/layouts/sidebar/bookmark-entry.php
+++ b/templates/element/layouts/sidebar/bookmark-entry.php
@@ -1,5 +1,8 @@
 <?php
     use Cake\Routing\Router;
+    use Cake\ORM\TableRegistry;
+
+    $this->userSettingsTable = TableRegistry::getTableLocator()->get('UserSettings');
 
     $seed = 'sb-' . mt_rand();
     $icon = $entry['icon'] ?? '';
@@ -14,6 +17,8 @@
         $active = true;
     }
 
+    $validURI = $this->userSettingsTable->validURI($url);
+
     echo $this->Bootstrap->button([
         'nodeType' => 'a',
         'text' => h($label),
@@ -22,9 +27,9 @@
         'outline' => !$active,
         'size' => 'sm',
         'icon' => h($icon),
-        'class' => ['mb-1'],
+        'class' => ['mb-1', !$validURI ? 'disabled' : ''],
         'params' => [
-            'href' => h($url),
+            'href' => $validURI ? h($url) : '#',
         ]
     ]);
 ?>