Vulnerabilities / Simply Schedule Appointments / WPSEC-2026-2885
Simply Schedule Appointments <= 1.6.13.0 - Unauthenticated Availability Check Bypass via 'start_date' Parameter
Medium 5.3
CWE-20Fixed in 1.6.13.4
- ID
- WPSEC-2026-2885
- Plugin
- Simply Schedule Appointments (simply-schedule-appointments)
- Affected
- all versions before 1.6.13.4
- Remediation
- Update to 1.6.13.4 or later.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness
- CWE-20
- Usage
- Plugin Medium · Affected versions Medium among sites WPSec scans, 2026-11-12
- Attack surface
- Simply Schedule Appointments on WPSec AttackSurface
- Fix released
- Published
Description
The Simply Schedule Appointments plugin for WordPress is vulnerable to an availability check bypass via the 'start_date' parameter in all versions up to, and including, 1.6.13.0 due to improper validation of the date format when creating or updating appointments. A non-canonical value such as one with a ' +1 day' suffix is parsed by PHP as a different moment than the date MySQL stores. This makes it possible for unauthenticated attackers to create appointments in slots that are already booked or otherwise unavailable, resulting in double-bookings.
References
- https://wpsec.com/vuln/WPSEC-2026-2885/
- https://plugins.svn.wordpress.org/simply-schedule-appointments/tags/1.6.13.4/
- https://wordpress.org/plugins/simply-schedule-appointments/
Published by WPSec. Provided as is, without warranty. Corrections: contact us.
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