# WP Booking System <= 2.1.0.2 - Reflected Cross-Site Scripting via 'booking_id' Parameter

- **ID:** WPSEC-2026-0836
- **Plugin:** WP Booking System – Booking Calendar (`wp-booking-system`), https://wordpress.org/plugins/wp-booking-system/
- **Affected versions:** all versions before 2.1.0.3
- **Fixed in:** 2.1.0.3 (Update to 2.1.0.3 or later.)
- **Severity:** Medium 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/wp-booking-system
- **Fix released:** 2026-10-12
- **Published:** 2026-10-13
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0836/

## Description

The WP Booking System plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'booking_id' parameter on the edit calendar admin page in all versions up to, and including, 2.1.0.2 due to insufficient input sanitization and output escaping. The parameter value is echoed unescaped into an inline JavaScript call. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute in a logged-in administrator's session if they can trick the administrator into clicking a crafted link.

## References

- https://wpsec.com/vuln/WPSEC-2026-0836/
- https://plugins.svn.wordpress.org/wp-booking-system/tags/2.1.0.3/
- https://wordpress.org/plugins/wp-booking-system/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0836/

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.