CVE-2026-88764: Improper Privilege Management

The Simple Membership WordPress plugin before 4.7.8 does not validate that the membership level supplied in a PayPal payment notification matches the level configured for the paid payment button, allowing members to pay for a lower-priced membership while being granted a higher, more privileged...

CVE-2026-14936

The CVE concerns the Simple Membership WordPress plugin prior to version 4.7.7, where PayPal IPN verification is not performed against the site’s configured merchant account before activating a membership. This allows unauthenticated users to activate or extend memberships using PayPal payments t...

CVE-2026-12501

CVE-2026-12501 affects the WP Travel Engine plugin for WordPress, prior to version 6.8.2. The vulnerability arises because the plugin does not verify that an incoming PayPal IPN is sent to the site’s merchant account, nor that the paid amount matches the order total, before marking a booking as p...

CVE-2026-12501 WP Travel Engine < 6.8.2 - Unauthenticated Payment Bypass via Missing PayPal IPN Receiver and Amount Verification

The WP Travel Engine WordPress plugin before 6.8.2 does not verify that an incoming PayPal payment notification was sent to the site's configured merchant account, nor that the paid amount matches the order total, before marking a booking as paid, allowing unauthenticated attackers to mark bookin...

CVE-2026-12501: Insufficient Verification of Data Authenticity

The WP Travel Engine WordPress plugin before 6.8.2 does not verify that an incoming PayPal payment notification was sent to the site's configured merchant account, nor that the paid amount matches the order total, before marking a booking as paid, allowing unauthenticated attackers to mark bookin...

CVE-2026-13143 WP Travel < 11.8.1 - Unauthenticated Payment Bypass via Forged PayPal IPN

The WP Travel WordPress plugin before 11.8.1 does not verify PayPal Instant Payment Notifications through the PayPal post-back handshake before marking a booking paid, allowing unauthenticated attackers to forge a notification that flips an arbitrary pending booking to a paid and booked state at ...

CVE-2026-43928

FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the PayPalEmail payment adapter accepts PayPal IPN callbacks and credits the IPN-supplied amount mcgross to the client's balance without validating it against the invoice total. Combined with a $0.05...

EUVD-2026-39949

The RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login plugin for WordPress is vulnerable to Authentication Bypass via Insufficient Verification of Data Authenticity in all versions up to and including 6.0.8.6. This is due to the PayPal IPN callback handler...

GHSA-MMW7-WQ3C-WF9P WWBN AVideo Affected by a PayPal IPN Replay Attack Enabling Wallet Balance Inflation via Missing Transaction Deduplication in ipn.php

Summary The PayPal IPN v1 handler at plugin/PayPalYPT/ipn.php lacks transaction deduplication, allowing an attacker to replay a single legitimate IPN notification to repeatedly inflate their wallet balance and renew subscriptions. The newer ipnV2.php and webhook.php handlers correctly deduplicate...

CVE-2026-39366

WWBN AVideo is an open source video platform. In versions 26.0 and prior, the PayPal IPN v1 handler at plugin/PayPalYPT/ipn.php lacks transaction deduplication, allowing an attacker to replay a single legitimate IPN notification to repeatedly inflate their wallet balance and renew subscriptions...

CVE-2009-1366

Cross-site scripting XSS vulnerability in Website\admin\Sales\paypalipn.aspx in DotNetNuke DNN before 4.9.3 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors related to "name/value pairs" and "paypal IPN functionality."...