NotificationX plugin for WordPress 2.0.0 before 2.3.12 contains an unauthenticated SQL injection vulnerability that allows remote attackers to manipulate database queries by supplying an array-form 'id' parameter to /wp-json/notificationx/v1/notification/{id}. Attackers can pass id[1] with crafted SQL, such as time-based SLEEP payloads, along with an api_key derived from md5(home_url()), which flows unsanitized into Database::get_where_query to extract database contents. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-18.