Scheduling Plugin – Online Booking for WordPress < 3.5.18 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
- ID
- WPSEC-2026-0134
- Plugin
- Scheduling Plugin – Online Booking for WordPress (calendar-booking)
- Affected
- all versions before 3.5.18
- Remediation
- Update to 3.5.18 or later.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Weakness
- CWE-79
- Usage
- Plugin Low · Affected versions None seen among sites WPSec scans, 2026-10-22
- Attack surface
- Scheduling Plugin – Online Booking for WordPress on WPSec AttackSurface
- Fix released
- Published
Description
The Scheduling Plugin – Online Booking for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'services' attribute of the 'startbooking_cta' shortcode and the 'service' attribute of the single-service 'startbooking' shortcode and block in all versions up to, and including, 3.5.17. This is due to insufficient input sanitization and output escaping: both values are placed into link href attributes without escaping. This makes it possible for authenticated attackers with contributor-level access and above to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Version 3.5.11 escaped only the shortcode data attributes (CVE-2024-23517) and left these link attributes unescaped.
References
- https://wpsec.com/vuln/WPSEC-2026-0134/
- https://plugins.svn.wordpress.org/calendar-booking/tags/3.5.18/
- https://wordpress.org/plugins/calendar-booking/
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