diff --git a/app/code/core/Mage/Newsletter/Model/Template.php b/app/code/core/Mage/Newsletter/Model/Template.php
index 48eb553e3d9..8149d8983e3 100644
--- a/app/code/core/Mage/Newsletter/Model/Template.php
+++ b/app/code/core/Mage/Newsletter/Model/Template.php
@@ -181,7 +181,7 @@ public function getTemplateTextPreprocessed()
             $this->setTemplateTextPreprocessed($this->getProcessedTemplate());
         }
 
-        return $this->getData('template_text_preprocessed');
+        return (string) $this->getData('template_text_preprocessed');
     }
 
     /**
diff --git a/app/code/core/Mage/SalesRule/Model/Resource/Rule/Collection.php b/app/code/core/Mage/SalesRule/Model/Resource/Rule/Collection.php
index c14f18b6bf1..ced624783bf 100644
--- a/app/code/core/Mage/SalesRule/Model/Resource/Rule/Collection.php
+++ b/app/code/core/Mage/SalesRule/Model/Resource/Rule/Collection.php
@@ -79,7 +79,7 @@ public function setValidationFilter($websiteId, $customerGroupId, $couponCode =
             $select = $this->getSelect();
 
             $connection = $this->getConnection();
-            if (strlen($couponCode)) {
+            if (is_string($couponCode) && strlen($couponCode)) {
                 $select->joinLeft(
                     ['rule_coupons' => $this->getTable('salesrule/coupon')],
                     $connection->quoteInto(