CVE-2026-103301 in Payment Gateway for Telcell Plugin
Summary
by MITRE • 10/21/2026
The Payment Gateway for Telcell WordPress plugin before 2.0.5 does not verify the authenticity of incoming payment notifications, because the secret used to sign them is empty by default, allowing unauthenticated attackers to forge a valid notification and mark arbitrary WooCommerce orders as paid. The same handler also marks an attacker-chosen order as failed when given an invalid signature.
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Analysis
by VulDB Data Team • 10/21/2026
The vulnerability identified in the Payment Gateway for Telcell WordPress plugin prior to version 2.0.5 represents a critical failure in authentication logic within the payment processing workflow. This flaw stems from the default configuration where the secret key used to verify digital signatures of incoming payment notifications is left empty or null. In secure web application architecture, particularly when integrating with third-party payment gateways, it is imperative that all asynchronous callbacks and webhook handlers validate the integrity and authenticity of the data received. The absence of a non-empty shared secret means that the system cannot cryptographically prove that a notification originated from the legitimate Telcell payment processor rather than an external actor. This fundamental oversight allows any entity with network access to interact directly with the plugin's endpoint without possessing valid credentials or cryptographic keys, effectively bypassing all intended security controls designed to prevent unauthorized state changes in e-commerce transactions.
From a technical perspective, this vulnerability is classified under CWE-287, which denotes Improper Authentication, and specifically relates to CWE-345, Insufficient Verification of Data Authenticity. The attacker can craft HTTP POST requests containing arbitrary order identifiers and status parameters that mimic the structure expected by the plugin's handler. Because the signature verification logic relies on an empty secret, any provided or absent signature is accepted as valid. This allows a malicious actor to forge payment success notifications for orders they have not paid for, thereby marking them as completed in the WooCommerce database. Conversely, the vulnerability also permits denial of service attacks against specific transactions; by sending requests with invalid signatures that trigger error handling paths designed to mark orders as failed, an attacker can disrupt legitimate business operations and cause financial loss or customer dissatisfaction through artificial order cancellations.
The operational impact of this flaw is severe for any e-commerce site utilizing the Telcell payment gateway integration. The primary consequence is direct financial fraud, where attackers receive goods or services without actual payment by forcing the system to believe a transaction was successful. This undermines the core trust model of online commerce and can lead to significant revenue loss if not detected promptly. Additionally, the ability to arbitrarily mark orders as failed introduces operational instability, potentially causing inventory discrepancies, shipping errors for legitimate customers whose orders are incorrectly cancelled, and increased support overhead due to false negative payment notifications. The lack of authentication also exposes the system to potential automated scanning attacks where bots continuously attempt to manipulate order statuses at scale, further exacerbating the risk to business continuity.
Mitigation strategies must focus on immediate remediation through software updates and configuration hardening. Administrators should upgrade the Payment Gateway for Telcell WordPress plugin to version 2.0.5 or later, as this release addresses the authentication flaw by ensuring a valid secret key is required and properly validated during notification processing. In cases where upgrading is not immediately feasible, temporary mitigations include restricting access to the payment webhook endpoint via IP whitelisting if the gateway provider publishes static source IPs, although this is less robust than cryptographic verification. Furthermore, implementing additional server-side validation checks, such as verifying order existence and ensuring that status changes are logged with audit trails, can help detect anomalous activity. Long-term security posture should involve regular audits of third-party plugin integrations to ensure they adhere to industry standards for secure API communication, including the use of strong cryptographic signatures and adherence to OWASP guidelines for securing web applications against injection and authentication bypass attacks aligned with MITRE ATT&CK techniques such as T1078 Valid Accounts or T1496 Resource Hijacking depending on exploitation context.