CVE-2026-91109 json
Simply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' Parameter
published 2026-10-01 39 d ago modified 2026-10-03 36 d ago also EUVD-2026-90466
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 36 d ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
Affected products
- croixhaug Simply Schedule Appointments
Classification
- Weakness
-
- CWE-639 Authorization Bypass Through User-Controlled Key
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/d1cd3de2-16ca-4f95-ad6f-47cfbe00c959?source=cve
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.12.27/includes/class-appointment-model.php#L3160
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.12.27/includes/class-appointment-model.php#L1966
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.12.27/includes/class-appointment-model.php#L2315
- plugins.trac.wordpress.org /browser/simply-schedule-appointments/tags/1.6.12.27/includes/class-db-model.php#L348
- plugins.trac.wordpress.org /changeset/3709365/simply-schedule-appointments/trunk/includes/class-appointment-model.php
Sources
- CVE List CVE-2026-91109
- NVD CVE-2026-91109
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.