CVE-2026-106166 in NEX-Forms Plugin
Summary
by MITRE • 10/14/2026
The NEX-Forms WordPress plugin before 9.3.1 does not perform any authorization, ownership or request-validation checks before updating stored form entries, allowing unauthenticated attackers to overwrite, permanently erase, reassign or append to any previously submitted form entry by referencing its sequential identifier.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified in the NEX-Forms WordPress plugin prior to version 9.3.1 represents a critical failure in access control mechanisms within the application's backend logic. This flaw is classified under CWE-269, which denotes Improper Privilege Control, as it allows an actor with lower privileges or no authentication at all to perform actions that should be restricted to authorized users. The core technical issue stems from the absence of server-side validation checks when processing requests intended to update stored form entries. Specifically, the plugin fails to verify whether the requesting user has ownership over the specific data record being modified, nor does it validate the integrity or origin of the request parameters beyond basic structural requirements. This lack of authorization logic means that any sequential identifier associated with a previously submitted form entry can be targeted by an external actor without requiring valid session cookies, API keys, or administrative credentials.
From a technical perspective, this vulnerability enables unauthenticated attackers to manipulate data stored within the WordPress database through direct manipulation of HTTP requests. By referencing the unique sequential ID assigned to each form submission, an attacker can send crafted POST requests that trigger update operations on arbitrary records. The operational impact is severe because it allows for multiple malicious outcomes including overwriting legitimate user submissions with false information, permanently erasing critical data which leads to a loss of integrity and potentially availability if backups are not maintained, reassigning ownership of entries to different users or accounts, and appending additional malicious fields or scripts to existing forms. This capability effectively breaks the trust boundary between public-facing form interfaces and private administrative data stores, turning user-submitted content into an attack vector for further exploitation such as cross-site scripting if the overwritten data is later rendered without proper sanitization in other parts of the application.
The security implications extend beyond simple data corruption. Because WordPress plugins often handle sensitive personal information or business-critical workflows via forms like contact pages, registration systems, or payment processing interfaces, this vulnerability compromises confidentiality and integrity at a systemic level. Attackers can use this flaw to deface websites by altering public-facing form outputs if they are displayed on the frontend, or more dangerously, escalate privileges if the overwritten data influences administrative decisions or triggers downstream processes that assume data authenticity. Furthermore, in environments where NEX-Forms integrates with third-party services via webhooks or API exports, tampered data could propagate errors or malicious payloads to external systems, amplifying the blast radius of the initial compromise.
To mitigate this vulnerability, immediate action is required by upgrading the NEX-Forms plugin to version 9.3.1 or later where these authorization checks have been implemented. Administrators should ensure that all WordPress installations are kept up-to-date with security patches from official repositories. In addition to patching, implementing a Web Application Firewall can provide an additional layer of defense by detecting and blocking anomalous request patterns associated with mass parameter manipulation or unauthorized access attempts. It is also advisable to review server logs for any signs of exploitation prior to the update, such as unusual spikes in form submission updates from single IP addresses or requests containing sequential ID ranges that suggest automated scanning activity. Regular security audits focusing on input validation and authorization logic across all custom plugins are recommended to prevent similar flaws arising from inconsistent implementation practices within the WordPress ecosystem.