CVE-2026-92978 in User Registration & Membership Plugin
Summary
by MITRE • 10/17/2026
The User Registration & Membership – Free & Paid Memberships, Subscriptions, Content Restriction, User Profile, Custom User Registration & Login Builder plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 5.2.8 This is due to missing or incorrect nonce validation on the trigger_bulk_action function. This makes it possible for unauthenticated attackers to force administrators to approve pending user registrations or deny arbitrary user accounts, locking targeted users out of the site via a forged request granted they can trick a site administrator into performing an action such as clicking on a link. An attacker can bypass the earlier nonce check in trigger_query_actions() by supplying an empty new_role parameter, which causes that handler to return early and cede control to the unprotected trigger_bulk_action() handler; the exit() call at the end of that handler additionally prevents WordPress core's own bulk-users nonce validation from executing.
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Analysis
by VulDB Data Team • 10/17/2026
The User Registration & Membership plugin for WordPress contains a critical Cross-Site Request Forgery vulnerability affecting all versions up to and including 5.2.8, classified under CWE-352 as an improper restriction of excessive authentication attempts or CSRF due to missing validation mechanisms. This flaw stems from the absence or incorrect implementation of nonce verification within the trigger_bulk_action function, which is responsible for processing bulk administrative actions related to user management. The vulnerability allows unauthenticated attackers to craft malicious requests that exploit the trust a WordPress site places in its administrators, enabling them to force state-changing operations without proper authorization checks.
The technical execution of this attack relies on manipulating the request flow within the plugin's PHP handlers. An attacker can bypass an earlier nonce check located in the trigger_query_actions function by supplying an empty new_role parameter. This specific input causes that handler to return early, effectively ceding control to the subsequent and unprotected trigger_bulk_action handler. Furthermore, the presence of an exit() call at the end of this handler prevents WordPress core from executing its own bulk-users nonce validation logic, thereby removing a critical layer of security defense that would normally verify the legitimacy of the request origin.
The operational impact of this vulnerability is significant for site administrators and registered users alike. An attacker who can trick a logged-in administrator into clicking on a malicious link or loading an image with a forged payload can force the approval of pending user registrations, potentially allowing unauthorized individuals to gain access to restricted areas of the website. Conversely, attackers can also deny arbitrary user accounts, effectively locking targeted legitimate users out of the site by revoking their permissions through forged administrative actions. This dual capability disrupts both security posture and availability for end-users relying on the platform.
To mitigate this risk, immediate action is required from all administrators using affected versions of the plugin. The primary remediation step is to upgrade the User Registration & Membership plugin to a version newer than 5.2.8, where these nonce validation issues have been addressed by the developers. Until an update is applied, site owners should consider restricting administrative access through IP whitelisting or multi-factor authentication to reduce the likelihood of successful social engineering attacks that lead to CSRF exploitation. Additionally, implementing strict Content Security Policy headers can help mitigate some aspects of cross-site scripting and request forgery vectors, although upgrading remains the definitive solution for this specific code-level flaw aligned with ATT&CK techniques related to privilege escalation and account manipulation.