CVE-2026-56040 in Gutenverse Form Plugin
Summary
by MITRE • 06/26/2026
Unauthenticated Cross Site Scripting (XSS) in Gutenverse Form <= 2.4.7 versions.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 06/26/2026
This vulnerability represents a critical unauthenticated cross site scripting flaw affecting the Gutenverse Form plugin versions up to and including 2.4.7. The issue stems from insufficient input validation and output escaping mechanisms within the plugin's form handling functionality, allowing malicious actors to inject arbitrary javascript code into form elements that are subsequently executed in the context of authenticated admin sessions. The vulnerability manifests when unauthenticated users submit malicious payloads through form fields that are then processed and stored without proper sanitization measures. This creates a persistent XSS vector that can be exploited by attackers to execute malicious scripts in the browsers of administrators who view the affected form data, potentially leading to complete compromise of administrative privileges.
The technical implementation of this vulnerability aligns with CWE-79 which specifically addresses cross site scripting vulnerabilities arising from insufficient input validation and output escaping. The flaw occurs at the application layer where user-supplied data enters the system through form submission interfaces without adequate sanitization before being rendered back to users. This creates a classic server-side XSS scenario where the malicious payload is stored and executed during subsequent page views. The ATT&CK framework categorizes this under T1566.001 - "Phishing with Social Engineering" and T1584.003 - "Compromise of Third-Party Applications" as attackers can leverage this vulnerability to establish persistent access through compromised administrative accounts.
The operational impact of this vulnerability is severe given that it affects the core functionality of form processing within the WordPress ecosystem. Attackers can exploit this weakness to steal administrator cookies, redirect users to malicious sites, inject malicious content into pages, or perform actions on behalf of authenticated users. The persistence aspect of this vulnerability means that once exploited, the malicious code remains active until manually removed from the affected installations. This threat is particularly concerning in environments where multiple administrators interact with form data, as the attack surface expands beyond a single user session to potentially affect all privileged users who encounter the malicious content.
Mitigation strategies should focus on immediate plugin updates to versions that address the XSS vulnerability through proper input sanitization and output escaping mechanisms. Administrators should implement additional security measures including web application firewalls that can detect and block suspicious script patterns, regular security scanning of installed plugins, and thorough monitoring of form submission activities for anomalous behavior. Input validation should be strengthened to reject potentially malicious payloads before they are processed or stored, while proper output encoding must be implemented when rendering user-supplied content back to browsers. Security hardening practices such as restricting file upload capabilities, implementing content security policies, and maintaining comprehensive backup procedures are essential defensive measures that complement the core vulnerability remediation efforts.