diff --git a/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php b/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
index a36b9f0d0..017891de8 100644
--- a/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
+++ b/system/src/Grav/Framework/Flex/Pages/Traits/PageLegacyTrait.php
@@ -366,9 +366,14 @@ trait PageLegacyTrait
      */
     public function blueprintName(): string
     {
-        $blueprint_name = filter_input(INPUT_POST, 'blueprint', FILTER_SANITIZE_STRING) ?: $this->template();
+        if (!isset($_POST['blueprint'])) {
+            return $this->template();
+        }
 
-        return $blueprint_name;
+        $post_value = $_POST['blueprint'];
+        $sanitized_value = htmlspecialchars(strip_tags($post_value), ENT_QUOTES, 'UTF-8');
+
+        return $sanitized_value ?: $this->template();
     }
 
     /**