CVE-2025-12787 Overview
CVE-2025-12787 affects the Hydra Booking — Appointment Scheduling & Booking Calendar plugin for WordPress in all versions up to and including 1.1.27. The vulnerability resides in the tfhb_meeting_form_submit_callback function, which generates booking cancellation tokens using insufficiently random values and relies on a globally shared nonce. Unauthenticated attackers can brute force the tfhb_meeting_form_cencel AJAX endpoint to cancel arbitrary bookings. The flaw is categorized under [CWE-330: Use of Insufficiently Random Values].
Critical Impact
Unauthenticated attackers can enumerate and cancel arbitrary bookings on any site running Hydra Booking <= 1.1.27, disrupting business operations and appointment integrity.
Affected Products
- Hydra Booking — Appointment Scheduling & Booking Calendar plugin for WordPress
- All versions up to and including 1.1.27
- Fixed in version 1.1.28
Discovery Timeline
- 2025-11-11 - CVE-2025-12787 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-12787
Vulnerability Analysis
The vulnerability stems from weak randomness in the token generation logic used to authorize booking cancellations. The tfhb_meeting_form_submit_callback function produces cancellation tokens with insufficient entropy, making them predictable. Compounding this, the plugin uses a globally shared nonce rather than per-user or per-session values. Attackers can iterate token candidates against the tfhb_meeting_form_cencel AJAX endpoint until a valid one is accepted. The endpoint accepts requests without authentication, allowing remote exploitation over the network.
Root Cause
The root cause is the use of insufficiently random values [CWE-330] to construct cancellation tokens. Combined with a globally shared nonce, the security check that should tie cancellation requests to a specific booking and requester is effectively bypassable through brute force. The plugin's WordPress.org repository changeset for version 1.1.28 revises the token generation and validation logic in HydraBookingShortcode.php.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker sends automated POST requests to the tfhb_meeting_form_cencel AJAX endpoint, cycling through candidate token values. When a token matches an existing booking, the request cancels that booking. The impact is limited to integrity — bookings can be canceled — while confidentiality and availability of the underlying WordPress site are not directly affected. See the Wordfence Vulnerability Report for additional technical detail.
Detection Methods for CVE-2025-12787
Indicators of Compromise
- High-volume POST requests to admin-ajax.php with the action=tfhb_meeting_form_cencel parameter from a single source IP.
- Sequential or randomized token values submitted to the cancellation endpoint within short time windows.
- Unexpected booking status changes to canceled without corresponding user activity in application logs.
Detection Strategies
- Inspect web server access logs for repeated requests to admin-ajax.php containing tfhb_meeting_form_cencel with varying token parameters.
- Enable WordPress plugin audit logging to correlate booking cancellations with originating IP addresses and user agents.
- Deploy a web application firewall rule to flag brute force patterns against the AJAX endpoint.
Monitoring Recommendations
- Alert on request rates above baseline for admin-ajax.php calls tied to the Hydra Booking plugin.
- Track booking cancellation events and compare against expected customer-initiated activity.
- Monitor for scanner user agents and known WordPress vulnerability probing tools targeting plugin endpoints.
How to Mitigate CVE-2025-12787
Immediate Actions Required
- Update the Hydra Booking plugin to version 1.1.28 or later immediately.
- Audit recent booking cancellations for the past several weeks and notify affected customers where appropriate.
- Restrict access to admin-ajax.php behind a web application firewall with rate limiting.
Patch Information
The vendor released version 1.1.28 of Hydra Booking, which revises the token generation logic in HydraBookingShortcode.php. Review the WordPress Plugin Change Log for the exact code changes. Sites managed through automatic updates should confirm the plugin has been upgraded.
Workarounds
- If patching cannot be performed immediately, deactivate the Hydra Booking plugin until the update is applied.
- Apply WAF rules to block or rate-limit requests to admin-ajax.php with action=tfhb_meeting_form_cencel.
- Require customers to confirm cancellations through an out-of-band channel such as email verification until the fix is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
