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CVE-2017-20206

Appointments <= 2.2.1 - Unauthenticated PHP Object Injection

Published: Oct 18, 2025Updated: Dec 23, 2025 Sources: CVE List NVDCWE-502
9.8CRITICAL
NVD MITRE
EPSS Score
0.7%
Top 52.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Nuclei

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-502

Affected Products

wpmudev
commercialaka broken link checker, forminator forms
AppointmentsOn-premCMS Plugin
Web & CMS Plugins / wordpress-plugin
and 1 more affected products View all →

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

3 techniques
Execution
Initial Access
View detailed technique mapping

References

https://www.wordfence.com/threat-intel/vulnerabilities/id/7e8f230e-3f96-4efd-806d-72725b960303?source=cve
wordfence.com
https://www.wordfence.com/blog/2017/10/3-zero-day-plugin-vulnerabilities-exploited-wild/
wordfence.com
https://plugins.trac.wordpress.org/changeset/1733186/appointments
plugins.trac.wordpress.org
News mentions
Could not load news mentions.

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