diff --git a/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit.php b/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit.php
index e15eebe00fe..58f2654e09b 100644
--- a/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit.php
+++ b/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit.php
@@ -301,6 +301,6 @@ public function getIsConfigured()
      */
     public function getSelectedTabId()
     {
-        return addslashes(htmlspecialchars($this->getRequest()->getParam('tab')));
+        return addslashes(htmlspecialchars($this->getRequest()->getParam('tab', '')));
     }
 }
diff --git a/app/code/core/Mage/Adminhtml/Controller/Report/Abstract.php b/app/code/core/Mage/Adminhtml/Controller/Report/Abstract.php
index 170e7663f20..d6fe0a113f1 100644
--- a/app/code/core/Mage/Adminhtml/Controller/Report/Abstract.php
+++ b/app/code/core/Mage/Adminhtml/Controller/Report/Abstract.php
@@ -72,7 +72,7 @@ public function _initReportAction($blocks)
             $blocks = [$blocks];
         }
 
-        $requestData = Mage::helper('adminhtml')->prepareFilterString($this->getRequest()->getParam('filter'));
+        $requestData = Mage::helper('adminhtml')->prepareFilterString($this->getRequest()->getParam('filter', ''));
         $requestData = $this->_filterDates($requestData, ['from', 'to']);
         $requestData['store_ids'] = $this->getRequest()->getParam('store_ids');
         $params = new Varien_Object();
diff --git a/app/code/core/Mage/Adminhtml/controllers/Report/StatisticsController.php b/app/code/core/Mage/Adminhtml/controllers/Report/StatisticsController.php
index 7d478999bee..21faebfe237 100644
--- a/app/code/core/Mage/Adminhtml/controllers/Report/StatisticsController.php
+++ b/app/code/core/Mage/Adminhtml/controllers/Report/StatisticsController.php
@@ -60,7 +60,7 @@ public function _initReportAction($blocks)
             $blocks = [$blocks];
         }
 
-        $requestData = Mage::helper('adminhtml')->prepareFilterString($this->getRequest()->getParam('filter'));
+        $requestData = Mage::helper('adminhtml')->prepareFilterString($this->getRequest()->getParam('filter', ''));
         $requestData = $this->_filterDates($requestData, ['from', 'to']);
         $requestData['store_ids'] = $this->getRequest()->getParam('store_ids');
         $params = new Varien_Object();
diff --git a/app/code/core/Mage/Catalog/Block/Product/List/Toolbar.php b/app/code/core/Mage/Catalog/Block/Product/List/Toolbar.php
index 7b8bdc9d783..db2d39b46cc 100644
--- a/app/code/core/Mage/Catalog/Block/Product/List/Toolbar.php
+++ b/app/code/core/Mage/Catalog/Block/Product/List/Toolbar.php
@@ -356,7 +356,7 @@ public function getCurrentDirection()
         }
 
         $directions = ['asc', 'desc'];
-        $dir = strtolower($this->getRequest()->getParam($this->getDirectionVarName()));
+        $dir = strtolower($this->getRequest()->getParam($this->getDirectionVarName(), ''));
         if ($dir && in_array($dir, $directions)) {
             if ($dir == $this->_direction) {
                 Mage::getSingleton('catalog/session')->unsSortDirection();