CVE-2026-103067 in Membership Plugin
Summary
by MITRE • 10/01/2026
Cross-Site Request Forgery (CSRF) vulnerability in Memberful Memberful - Membership Plugin memberful-wp allows Cross Site Request Forgery.This issue affects Memberful - Membership Plugin: from n/a through 1.81.0.
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Analysis
by VulDB Data Team • 10/01/2026
The identified security flaw represents a classic Cross-Site Request Forgery (CSRF) vulnerability within the Memberful membership plugin for WordPress, specifically affecting versions ranging from initial releases up to version 1.81.0. CSRF attacks exploit the trust that a web application has in the user's browser by tricking the victim into performing actions they did not intend to perform. In this context, an attacker can craft malicious requests that are automatically submitted by the victim's browser while authenticated with their Memberful account credentials stored in cookies or session tokens. Because the vulnerability lies within the plugin’s handling of state-changing operations without adequate verification of the request origin, any user who is logged into the WordPress dashboard and visits a maliciously crafted page can inadvertently trigger administrative actions on behalf of the attacker. This type of attack does not require stealing sensitive data directly but rather allows an adversary to manipulate the application's functionality as if they were the legitimate user, leading to potential unauthorized modifications or deletions within the membership system.
From a technical perspective, the root cause typically involves the absence of anti-CSRF tokens in forms and AJAX requests that modify critical state, such as changing subscription statuses, updating member details, or altering payment settings. Without these unique, unpredictable values tied to the user's session, the server cannot distinguish between legitimate user-initiated actions and forged requests originating from third-party sites. This deficiency aligns with CWE-352, which defines Cross-Site Request Forgery as a vulnerability where an attacker causes a authenticated user to submit a request that performs unwanted functions on behalf of that user. The impact is significant because membership plugins often handle sensitive financial data and personal information; therefore, successful exploitation could lead to unauthorized changes in subscription tiers, cancellation of paid memberships without consent, or even the creation of new administrative accounts if privilege escalation paths exist within the affected codebase.
The operational impact extends beyond immediate functional disruption to include potential reputational damage and loss of trust among subscribers who rely on the platform for secure access to content or services. Attackers may use this vulnerability to disrupt business operations by cancelling subscriptions, altering billing information, or deleting member profiles, thereby causing financial losses and customer churn. Furthermore, if the compromised account has administrative privileges, the attacker could install further malicious plugins or modify site configurations, leading to a complete compromise of the WordPress environment. This scenario is often categorized under MITRE ATT&CK technique T1566.002, which refers to Spearphishing via Link attacks where social engineering techniques are combined with technical exploitation like CSRF to achieve initial access and subsequent lateral movement within the target infrastructure.
To mitigate this vulnerability, immediate action should be taken by upgrading the Memberful plugin to a version later than 1.81.0, as developers typically address such issues in subsequent releases through the implementation of proper anti-CSRF mechanisms. For organizations unable to upgrade immediately due to compatibility constraints or other operational reasons, temporary mitigations include implementing strict Content Security Policy headers that restrict form submissions and ensuring that all state-changing requests require explicit user interaction rather than automatic submission. Additionally, enabling SameSite cookie attributes can help prevent browsers from sending session cookies in cross-site contexts, thereby reducing the effectiveness of CSRF attacks. Regular security audits and penetration testing should also be conducted to identify similar weaknesses across other plugins and themes installed on the WordPress instance, ensuring a holistic approach to web application security that adheres to industry best practices for preventing unauthorized state changes.