The WP Recipe Maker plugin for WordPress is vulnerable to an Insecure Direct Object Reference (IDOR) in versions up to, and including, 10.3.2. This is due to the /wp-json/wp-recipe-maker/v1/integrations/instacart REST API endpoint's permission_callback being set to __return_true and a lack of subsequent authorization or ownership checks on the user-supplied recipeId. This makes it possible for unauthenticated attackers to overwrite arbitrary post metadata (wprm_instacart_combinations) for any post ID on the site via the recipeId parameter.