【中文导读】Appointments 存在反序列化风险（严重风险）。具体受影响版本、触发条件和修复方案以 NVD/厂商公告为准。 【原始描述】The Appointments plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.2.1 via deserialization of untrusted input from the `wpmudev_appointments` cookie. This allows unauthenticated attackers to inject a PHP Object. Attackers were actively exploiting this vulnerability with the WP_Theme() class to create backdoors.