LearnPress Course Wishlist Add-on before 4.1.2 contains an insecure direct object reference vulnerability that allows remote attackers to manipulate any user's course wishlist by supplying an arbitrary user_id parameter to the render_button callback instead of relying on the session identity. Attackers can exploit the publicly accessible load_content_via_ajax REST route, which only requires a public wp_rest nonce, to add or remove courses from any user's wishlist and determine whether a given course is wishlisted by iterating user_id and course_id values.