CVE-2026-11901
The WP Hotel Booking plugin for WordPress is vulnerable to Insufficient Verification of Data Authenticity in all versions up to, and including, 2.3.1. This is due to the web_hook_process_paypal_standard() IPN handler selecting its PayPal validation endpoint from the attacker-controlled $_REQUEST['test_ipn'] parameter, force-upgrading any pending transaction to completed when test_ipn=1, and omitting post-verification checks on receiver_email, mc_currency, and txn_id uniqueness after receiving a VERIFIED response from PayPal. This makes it possible for unauthenticated attackers to mark arbitrary hotel bookings as fully paid without submitting genuine payment to the merchant — either by routing IPN validation through PayPal's sandbox using a free sandbox account, or by replaying a previously verified IPN from a nominal payment to an attacker-controlled PayPal account. An attacker requires only a free PayPal sandbox account (or any PayPal account) to obtain a VERIFIED response; no site credentials or special configuration are needed.
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