Is CVE-2017-20206 actively exploited?

No active exploitation of CVE-2017-20206 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2017-20206 be exploited remotely?

Yes. CVE-2017-20206 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2017-20206?

CVE-2017-20206 has a CVSS score of 9.8 (CRITICAL).

HOME VULNERABILITIESCVE-2017-20206

CRITICAL

CVE-2017-20206

CWE-502Published: October 18, 2025· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official 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.

NVD Source

Risk Analysis

This critical PHP Object Injection vulnerability in the Appointments plugin for WordPress, affecting versions up to 2.2.1, allows unauthenticated attackers to inject a PHP Object. The flaw, via deserialization of untrusted input from the 'wpmudev_appointments' cookie, has been actively exploited to create backdoors. The CVSS score of 9.8 highlights the severe impact and ease of exploitation, though no EPSS score is available to indicate exploitation likelihood.

No public exploit is currently known for this vulnerability, but active exploitation has been observed. This flaw is remotely exploitable over the network without requiring any user interaction.

Recommended Action

Organizations using the Appointments plugin should update to a patched version beyond 2.2.1. Implement robust input validation and avoid deserializing untrusted data.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2017-20206 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-502): Insecure deserialization vulnerabilities allow attackers to inject malicious objects during deserialization, potentially enabling remote code execution.