Security patch 6788 can cause problems in the displaying of static blocks. This issue is related to changes that the patch applies to the work of Mage_Core_Model_Email_Template_Filter class that is located in the following file: app/code/core/Mage/Core/Model/Email/Template/Filter.php. This class contains blockDirective method that creates a block and returns html-code for this block. The patch 6788 adds a code to this method and this code checks whether the block is allowed or not.
Before installing the patch the code for creation of blocks looks as following: (more…)