a NULL pointer dereference located in update_depend_map_for_order function in sql/sql_select.cc at line 16641

This vulnerability is located in MariaDB’s update_depend_map_for_order function in sql/sql_select.cc at line 16641. It involves a NULL pointer dereference when accessing (*tab)->ref.depend_map without verifying that tab is non-null. This can be triggered during the optimization phase of a SELECT query with specific ORDER BY clauses, potentially allowing an attacker to cause a segmentation fault and crash the server (DoS).