CVE-2026-85123 in Easy Form Builder Plugin
Summary
by MITRE • 09/18/2026
The Easy Form Builder by WhiteStudio WordPress plugin before 4.2.0 does not validate a submitted value against the stored configuration for some of its form types, allowing unauthenticated users to create WordPress accounts on a site whose owner has disabled registration.
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified in versions of the Easy Form Builder by WhiteStudio prior to version 4.2.0 represents a critical authentication bypass and account creation flaw rooted in insufficient input validation mechanisms. This security defect specifically affects form types that handle user data submission, where the plugin fails to cross-reference submitted values against the site's existing configuration settings. In standard WordPress environments, administrators can disable public registration through specific dashboard settings intended to restrict new account creation to authenticated users only. However, due to this logical error in the plugin’s processing logic, these administrative controls are effectively circumvented when a user interacts with vulnerable form instances.
From a technical perspective, the core issue lies in the absence of proper validation checks during the submission handling process. When a visitor submits data through an Easy Form Builder form that is susceptible to this flaw, the backend script does not verify whether public registration is disabled on the target WordPress installation. Instead, it proceeds with creating a new user account based solely on the provided input fields, such as username and email address. This lack of contextual awareness regarding the site's security posture allows unauthenticated external actors to register valid credentials without any prior authorization or interaction with standard login portals. The flaw is particularly dangerous because it exploits legitimate functionality for malicious purposes, making detection by automated security tools more difficult compared to direct exploitation attempts against known endpoints.
The operational impact of this vulnerability is severe, as it directly compromises the integrity and access control mechanisms of the affected WordPress site. By allowing unauthenticated users to create accounts, attackers can establish persistent footholds within the application environment. These newly created accounts may be assigned low-level roles such as subscriber or contributor, depending on default settings, which nonetheless provides a platform for further exploitation. Attackers can use these credentials to post spam content, harass other users, or attempt privilege escalation attacks against higher-privileged administrators. Furthermore, the presence of unauthorized user accounts complicates forensic analysis and audit trails, as legitimate administrative actions may be obscured by activity originating from these maliciously created identities.
This vulnerability aligns with CWE-284, which describes Improper Access Control, specifically regarding the failure to enforce proper restrictions on unauthenticated users. Additionally, it maps to MITRE ATT&CK technique T1078, Valid Accounts, where adversaries obtain legitimate credentials to maintain access and evade detection. The exploitation vector is classified as remote with no additional prerequisites other than network connectivity to the vulnerable site, making it a high-risk issue for any public-facing WordPress installation utilizing this plugin version.
To mitigate this risk, administrators must immediately update the Easy Form Builder plugin to version 4.2.0 or later, where the validation logic has been corrected to respect the global registration settings of the WordPress environment. Until an upgrade is performed, site owners should consider disabling any forms that collect user data for account creation or implementing additional server-side checks via custom code snippets if available in their specific deployment context. Regular monitoring of user logs and audit trails can also help identify suspicious registration patterns indicative of exploitation attempts. Maintaining up-to-date software components remains the most effective defense against such logic-based vulnerabilities, ensuring that application behavior strictly adheres to configured security policies.