# Booking System <= 2.1.0.5 - Authenticated (Subscriber+) Missing Authorization to Add Booking Calendar Options Update

- **ID:** WPSEC-2026-1704
- **Plugin:** WP Booking System – Booking Calendar (`wp-booking-system`), https://wordpress.org/plugins/wp-booking-system/
- **Affected versions:** all versions before 2.1.0.6
- **Fixed in:** 2.1.0.6 (Update to 2.1.0.6 or later.)
- **Severity:** Medium 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-27)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/wp-booking-system
- **Fix released:** 2026-10-26
- **Published:** 2026-10-27
- **URL:** https://wpsec.com/vuln/WPSEC-2026-1704/

## Description

The WP Booking System plugin for WordPress is vulnerable to unauthorized modification of data via the 'wpbs_add_booking_save_calendar_options' AJAX action in all versions up to, and including, 2.1.0.5, due to a missing capability check and missing nonce validation on the wpbs_action_ajax_add_booking_save_calendar_options() function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the manual booking options stored for any calendar.

## References

- https://wpsec.com/vuln/WPSEC-2026-1704/
- https://plugins.svn.wordpress.org/wp-booking-system/tags/2.1.0.6/
- https://wordpress.org/plugins/wp-booking-system/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1704/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.