a NULL pointer dereference in the function Item_direct_view_ref::derived_field_transformer_for_where, located at sql/item.cc:7831

This MariaDB vulnerability is a NULL pointer dereference in the function Item_direct_view_ref::derived_field_transformer_for_where, located at sql/item.cc:7831. During a condition pushdown transformation for derived tables, the function calls find_producing_item(this, sel) where sel is not properly initialized, resulting in a segmentation fault. This can be triggered by crafted SQL queries involving views and complex WHERE clause transformations, leading to a crash and denial-of-service (DoS).