Description
The Simply Schedule Appointments plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.31 via the 'complete_group' parameter due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to disclose every co-booker's private per-appointment id_token (exposed as public_token) alongside their PII (name and email address), then use each leaked token to read, overwrite arbitrary appointment meta on, or cancel the co-booker's appointment via the same REST controller. Exploitation requires the attacker to possess a valid id_token for any single appointment within the targeted group booking.
References6
- plugins.trac.wordpress.org/browser/simply-schedule-appointments…
- plugins.trac.wordpress.org/browser/simply-schedule-appointments…
- plugins.trac.wordpress.org/browser/simply-schedule-appointments…
- plugins.trac.wordpress.org/browser/simply-schedule-appointments…
- plugins.trac.wordpress.org/changeset/3709365/simply-schedule-ap…
- www.wordfence.com/threat-intel/vulnerabilities/id/d1cd3de2-16ca…
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 24 · as of 10 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.