How severe is CVE-2017-20206?

CVE-2017-20206 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-20206 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-20206?

CVE-2017-20206 affects Wpmudev Appointments. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-20206?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2017-20206 have an EU (EUVD) identifier?

Yes. CVE-2017-20206 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2017-18924.

When was CVE-2017-20206 published?

CVE-2017-20206 was published on 2025-10-18 and last updated on 2026-06-17.

CVE-2017-20206

CVE-2017-20206 is a critical-severity vulnerability in Wpmudev Appointments with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2017-18924
Weakness: CWE-502
Affected product: Wpmudev Appointments
Published: 2025-10-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2017-20206?: 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.
How severe is CVE-2017-20206?: CVE-2017-20206 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-20206 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-20206?: CVE-2017-20206 affects Wpmudev Appointments. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-20206?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2017-20206 have an EU (EUVD) identifier?: Yes. CVE-2017-20206 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2017-18924.
When was CVE-2017-20206 published?: CVE-2017-20206 was published on 2025-10-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:wpmudev:appointments:*:*:*:*:*:wordpress:*:*

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