CVE-2026-77793 in RegistrationMagic Plugin
Summary
by MITRE • 09/02/2026
The RegistrationMagic WordPress plugin before 6.0.9.9 does not validate the total price of a paid registration server-side, allowing unauthenticated users to complete a paid registration without paying and obtain an activated account.
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Analysis
by VulDB Data Team • 09/02/2026
RegistrationMagic is a widely utilized WordPress plugin designed to facilitate user registration forms with various customization options, including support for paid registrations through integration with payment gateways such as PayPal or Stripe. The vulnerability identified in versions prior to 6.0.9.9 stems from a critical lack of server-side validation regarding the total price associated with a paid registration form. In secure application design, any financial transaction initiated by a client must be independently verified on the server side to ensure integrity and prevent tampering. However, this specific implementation relied heavily on client-supplied data or failed to cross-reference the submitted amount against the expected cost defined in the plugin configuration during the backend processing phase.
This architectural flaw allows unauthenticated attackers to manipulate the registration process by altering request parameters to set the payment amount to zero or a nominal value that bypasses actual financial transfer requirements. By exploiting this logic error, an attacker can submit a valid registration form while effectively circumventing the payment gateway's authentication and authorization mechanisms. The server processes the submission as complete because it does not verify whether the transaction was actually funded according to the configured price rules. Consequently, the system grants access privileges associated with the paid tier without requiring any monetary exchange.
The operational impact of this vulnerability is significant for organizations relying on RegistrationMagic for monetized user communities or subscription-based services. Unauthenticated users can obtain activated accounts that typically require payment, leading directly to revenue loss and potential abuse of premium features. Furthermore, since these accounts are fully activated, attackers may use them to conduct further malicious activities such as spamming, scraping protected content, or launching additional attacks from within the trusted network perimeter established by valid user status. This undermines the integrity of the business model and compromises the security posture of the WordPress site by increasing the attack surface with unauthorized privileged users.
From a classification perspective, this issue aligns with CWE-347: Improper Verification of Cryptographic Signature or more broadly CWE-862: Missing Authorization when considering that the user is not authorized to access paid features without payment verification. In terms of the MITRE ATT&CK framework, this vulnerability facilitates Initial Access through exploitation of client-side trust and can be categorized under T1078: Valid Accounts if the attacker uses the obtained credentials for subsequent lateral movement or persistence within the environment. The root cause is fundamentally a business logic error where financial constraints are not enforced at the point of transaction processing on the server side.
To mitigate this vulnerability, administrators must upgrade to version 6.0.9.9 or later of the RegistrationMagic plugin, which implements proper server-side validation for all paid registration forms. This update ensures that the total price is verified against configured rules before granting account activation and access privileges. Additionally, developers should adopt a defense-in-depth strategy by never trusting client-supplied data regarding financial amounts. All monetary values must be derived from secure server-side configurations or database lookups rather than input fields submitted by users. Implementing robust backend validation checks for every step of the payment workflow is essential to prevent similar logic flaws in future implementations and maintain the integrity of paid access controls.