Paymenter vulnerabilities

In Paymenter prior to 1.5.7, doUpgrade() relied on Service::upgradable to check for a pending upgrade and then incremented credit without a DB transaction or lock. An authenticated customer with an active downgradable service could submit concurrent downgrade requests, creating multiple upgrade records and incrementing the same credit balance multiple times.

Paymenter versions prior to 1.5.5 have a race condition in the credit payment implementation. The row lock (lockForUpdate()) is executed outside an active database transaction, making it ineffective in MySQL/MariaDB. Concurrent payment requests can read the same credit balance and reuse the same funds.

Paymenter before 1.5.1 has a vulnerability in the checkout component allowing authenticated users to inject arbitrary key-value pairs into server provisioning parameters, potentially overriding resource limits without privileges.

In Paymenter prior to version 1.5.0, the ticket creation endpoint accepts a user-supplied service identifier without enforcing ownership validation, allowing authenticated users to create support tickets referencing services belonging to other accounts by modifying the service ID in the request.

Paymenter before version 1.5.0 fails to invalidate the email verification state after an email change. A verified account retains its verified status even after switching to an unverified address. This could lead to abuse of features gated behind verified status.

Paymenter is a free open-source webshop solution for hosting services. In versions prior to 1.5.0, the PayPal webhook endpoint /extensions/paypal/webhook processes the PAYPAL-CERT-URL HTTP header without validation, allowing attackers to control server-side HTTP request destinations. This value is passed directly into a server-side HTTP request via file_get_contents without allowlist, validation, or signature verification. The vulnerability allows remote unauthenticated attackers to trigger HTTP GET requests to arbitrary external or internal endpoints, potentially leading to blind SSRF and access to internal network services.