Description
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.
Metrics
CVSS 3.1 9.8/10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| wpmudev | Appointments | < 2.2.2 |
References
- https://plugins.trac.wordpress.org/changeset/1733186/appointmentsPatch
- https://www.wordfence.com/blog/2017/10/3-zero-day-plugin-vulnerabilities-exploited-wild/Press/Media Coverage, Third Party Advisory
- https://www.wordfence.com/threat-intel/vulnerabilities/id/7e8f230e-3f96-4efd-806d-72725b960303?source=cveThird Party Advisory
Timeline
- Published
- Oct 18, 2025
- Last modified
- Jun 17, 2026
- NVD status
- Analyzed