CVE-2026-102388 in Forminator Plugin
Summary
by MITRE • 10/10/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in WPMU DEV Forminator forminator allows Stored XSS.This issue affects Forminator: from n/a through 1.57.3.
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Analysis
by VulDB Data Team • 10/10/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability is classified under the CWE-80 standard and manifests within the WPMU DEV Forminator plugin for WordPress in versions ranging from n/a through 1.57.3. The core technical deficiency lies in the application's failure to adequately sanitize user-supplied input before it is rendered back into web pages without proper encoding or validation. This oversight allows an attacker to inject malicious client-side scripts, such as JavaScript, which are then stored within the target system and executed when other users access the affected content.
This particular implementation constitutes a Stored XSS vulnerability rather than a reflected one, significantly increasing its severity and potential impact. In a typical web application workflow involving forms, user input is often saved to a database for later retrieval and display. When Forminator processes form submissions containing malicious script payloads, it fails to escape special characters or strip executable code before storing the data. Consequently, when an administrator or any other authorized user views the submitted form entries through the WordPress dashboard, the browser interprets the injected scripts as legitimate content from the trusted domain of the website. This bypasses same-origin policy protections that would otherwise prevent malicious sites from accessing sensitive information on a different site.
The operational impact of this vulnerability is substantial due to its persistent nature and high-privilege execution context. Since Forminator is frequently used by administrators to collect data, the stored XSS payload will execute in the security context of an administrator account when they review submissions. This allows attackers to perform actions such as stealing session cookies or authentication tokens, which can lead to complete account takeover. Furthermore, once control over an administrative account is established, the attacker can manipulate site settings, install additional malicious plugins, deface the website, or use the server as a pivot point for further network attacks. The ability to execute arbitrary JavaScript also enables phishing campaigns against other users who view the compromised form entries, potentially expanding the scope of the compromise beyond the initial target account.
From an offensive security perspective, this vulnerability aligns with several tactics in the MITRE ATT&CK framework. It directly supports the Execution tactic by allowing script execution within a browser environment and facilitates Credential Access through session hijacking techniques like cookie stealing or keylogging via injected input fields. The persistence of the payload means it can be leveraged for long-term access, supporting the Persistence and Collection tactics as well. Attackers often use this method to establish a foothold that remains active even after initial detection efforts if not properly remediated at the application level.
Mitigation strategies must address both immediate remediation and long-term defensive coding practices. The primary solution is to upgrade Forminator to version 1.57.4 or later, where the developers have implemented proper input sanitization and output encoding mechanisms to neutralize malicious scripts before they are stored or rendered. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include implementing a Web Application Firewall that can detect and block common XSS payloads in form submissions. Additionally, enforcing strict Content Security Policy headers on the WordPress site can restrict the execution of inline scripts, thereby reducing the impact even if an injection attempt succeeds. Developers should also adopt secure coding standards such as OWASP Top Ten guidelines, ensuring all user inputs are validated against expected formats and encoded appropriately for their context before being processed or displayed by the application.