The Paytm Payment Gateway WordPress plugin before 2.8.9 does not verify that payment callbacks genuinely originate from the payment provider when its secret key has not been configured, which is its state immediately after activation, allowing unauthenticated attackers to change the status of arbitrary orders, including marking unpaid orders as paid and reducing stock.

The Paytm Payment Gateway WordPress plugin before 2.8.9 does not properly escape data taken from payment callbacks before using it in a SQL statement, and the integrity check on those callbacks can be forged when the gateway is enabled without credentials, allowing unauthenticated users to perform SQL injection attacks.

The Paytm Payment Gateway WordPress plugin before 2.8.9 does not sanitize and escape data it stores from payment callbacks before outputting it in an admin page, and the integrity check on those callbacks can be forged when the gateway is enabled without credentials, allowing unauthenticated users to store scripts that will run in the session of a store administrator.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in integrationdevpaytm Paytm Payment Donation paytm-donation allows Stored XSS.This issue affects Paytm Payment Donation: from n/a through <= 2.3.3.

Server-Side Request Forgery (SSRF) vulnerability in Paytm Paytm Payment Gateway.This issue affects Paytm Payment Gateway: from n/a through 2.7.0.

A vulnerability in integrationdevpaytm Paytm Payment Gateway paytm-payments.This issue affects Paytm Payment Gateway: from n/a through <= 2.7.3.