CVE-2026-91109

Simply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' Parameter

Published Oct 1, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Croixhaug
Croixhaug simply Schedule Appointments
Wordpress-extensions
Wordpress-extensions simply Schedule Appointments
Vendors & Products Croixhaug
Croixhaug simply Schedule Appointments
Wordpress-extensions
Wordpress-extensions simply Schedule Appointments
Type Values Removed Values Added
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.
Title Simply Schedule Appointments <= 1.6.12.31 - Insecure Direct Object Reference to Authenticated (Subscriber+) Sensitive Information Disclosure via 'complete_group' Parameter
Weaknesses CWE-639
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Wordfence
Published
Updated
Oct 3, 2026, 3:42 PM
Reserved
Sep 14, 2026, 7:36 PM
Status
Deferred
Published
Oct 1, 2026, 4:18 AM
Modified
Oct 3, 2026, 4:16 PM