CVE-2017-20206Known exploitationNetwork attack vector

Unauthenticated site takeover via cookie deserialization

Published Oct 18, 2025 · Updated Oct 18, 2025

PHP object injection in WPMU DEV Appointments+ before 2.2.2 allows remote attackers to create PHP backdoors through a crafted cookie. The plugin passes the untrusted wpmudev_appointments cookie to PHP unserialize(), allowing a crafted WP_Theme object to fetch and write an attacker-controlled file. No authentication or user interaction is required; successful backdoor access grants control of the WordPress site.

CVSS severity9.8
Critical
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PHP object injection in WPMU DEV Appointments+ before 2.2.2 allows remote attackers to create PHP backdoors through a crafted cookie. The plugin passes the untrusted wpmudev_appointments cookie to PHP unserialize(), allowing a crafted WP_Theme object to fetch and write an attacker-controlled file. No authentication or user interaction is required; successful backdoor access grants control of the WordPress site.

The record

CVE
CVE-2017-20206
Published
Oct 18, 2025
Updated
Oct 18, 2025
Vendor
WPMU DEV
Product
Appointments+
Classifications
CWE-502, T1190, T1505.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <2.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPMU DEV · Appointments+version=* <2.2.2

Published CVSS scores

9.8WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application
T1505.003Web Shell

Public exploit references

No public exploit references are available in this record.

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Reported exploitation

Technologies

Your stack

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Your stack

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