diff --git a/classes/extravar/Extravar.class.php b/classes/extravar/Extravar.class.php
index ddda833a7..823effc5b 100644
--- a/classes/extravar/Extravar.class.php
+++ b/classes/extravar/Extravar.class.php
@@ -58,7 +58,7 @@ class ExtraVar
 
 		foreach($extra_keys as $val)
 		{
-			$obj = new ExtraItem($val->module_srl, $val->idx, $val->name, $val->type, $val->default, $val->desc, $val->is_required, $val->search, $val->value, $val->eid);
+			$obj = new ExtraItem($val->module_srl, $val->idx, $val->name, $val->type, $val->default, $val->desc, $val->is_required, $val->search, $val->value ?? null, $val->eid);
 			$this->keys[$val->idx] = $obj;
 		}
 	}
diff --git a/common/framework/parsers/dbquery/variablebase.php b/common/framework/parsers/dbquery/variablebase.php
index 4b86e2372..463bda5f3 100644
--- a/common/framework/parsers/dbquery/variablebase.php
+++ b/common/framework/parsers/dbquery/variablebase.php
@@ -294,6 +294,11 @@ class VariableBase
 		{
 			list($is_expression, $value) = $this->getDefaultValue();
 		}
+		else
+		{
+			$is_expression = null;
+			$value = null;
+		}
 		
 		return [$is_expression, $value];
 	}
diff --git a/modules/board/board.view.php b/modules/board/board.view.php
index b82bd8b05..da400c562 100644
--- a/modules/board/board.view.php
+++ b/modules/board/board.view.php
@@ -35,8 +35,8 @@ class boardView extends board
 		{
 			$this->page_count = $this->module_info->page_count;
 		}
-		$this->except_notice = $this->module_info->except_notice == 'N' ? FALSE : TRUE;
-		$this->include_modules = $this->module_info->include_modules ? explode(',', $this->module_info->include_modules) : [];
+		$this->except_notice = ($this->module_info->except_notice ?? '') == 'N' ? FALSE : TRUE;
+		$this->include_modules = ($this->module_info->include_modules ?? []) ? explode(',', $this->module_info->include_modules) : [];
 		if (count($this->include_modules) && !in_array($this->module_info->module_srl, $this->include_modules))
 		{
 			$this->include_modules[] = $this->module_info->module_srl;
@@ -546,7 +546,7 @@ class boardView extends board
 		}
 
 		// setup the list count to be serach list count, if the category or search keyword has been set
-		if($args->category_srl || $args->search_keyword)
+		if($args->category_srl ?? null || $args->search_keyword ?? null)
 		{
 			$args->list_count = $this->search_list_count;
 		}
diff --git a/modules/document/document.controller.php b/modules/document/document.controller.php
index 7caa3946d..c17b1dca7 100644
--- a/modules/document/document.controller.php
+++ b/modules/document/document.controller.php
@@ -2463,7 +2463,7 @@ class documentController extends document
 			$list[$category_srl] = $category_list[$i];
 		}
 		// Create the xml file without node data if no data is obtained
-		if(!$list)
+		if(!isset($list) || !$list)
 		{
 			$xml_buff = "<root />";
 			FileHandler::writeFile($xml_file, $xml_buff);
diff --git a/modules/document/document.model.php b/modules/document/document.model.php
index b396cdc0a..eed9cf3dc 100644
--- a/modules/document/document.model.php
+++ b/modules/document/document.model.php
@@ -707,7 +707,10 @@ class documentModel extends document
 
 		// Cleanup of category
 		$document_category = array();
-		self::_arrangeCategory($document_category, $menu->list, 0);
+		if (isset($menu) && isset($menu->list))
+		{
+			self::_arrangeCategory($document_category, $menu->list, 0);
+		}
 		return $document_category;
 	}
 
diff --git a/modules/file/file.admin.model.php b/modules/file/file.admin.model.php
index 89daed2bc..d48a1ea1e 100644
--- a/modules/file/file.admin.model.php
+++ b/modules/file/file.admin.model.php
@@ -75,9 +75,9 @@ class fileAdminModel extends file
 		elseif($obj->direct_download == 'N') $args->direct_download= 'N';
 		// Set variables
 		$args->sort_index = $obj->sort_index;
-		$args->page = $obj->page?? 1;
-		$args->list_count = $obj->list_count?? 20;
-		$args->page_count = $obj->page_count?? 10;
+		$args->page = isset($obj->page) ? ($obj->page ? $obj->page : 1) : 1;
+		$args->list_count = isset($obj->list_count) ? ($obj->list_count? $obj->list_count : 20) : 20;
+		$args->page_count = isset($obj->page_count) ? ($obj->page_count? $obj->page_count : 10) : 10;
 		$args->s_module_srl = $obj->module_srl;
 		$args->exclude_module_srl = $obj->exclude_module_srl;
 		if(toBool($obj->exclude_secret))
@@ -165,8 +165,8 @@ class fileAdminModel extends file
 	protected function _makeSearchParam(&$obj, &$args)
 	{
 		// Search options
-		$search_target = $obj->search_target ?? trim(Context::get('search_target'));
-		$search_keyword = $obj->search_keyword ?? trim(Context::get('search_keyword'));
+		$search_target = isset($obj->search_target)? ($obj->search_target? $obj->search_target : trim(Context::get('search_target'))) : trim(Context::get('search_target'));
+		$search_keyword = isset($obj->search_keyword)? ($obj->search_keyword? $obj->search_keyword : trim(Context::get('search_keyword'))) : trim(Context::get('search_keyword'));
 
 		if($search_target && $search_keyword)
 		{