CVE-2025-3487: Wpmudev Forminator Forms XSS Vulnerability

CVE-2025-3487 Overview

CVE-2025-3487 is a Stored Cross-Site Scripting (XSS) vulnerability in the Forminator Forms – Contact Form, Payment Form & Custom Form Builder plugin for WordPress. The flaw affects all versions up to and including 1.42.0. It stems from insufficient input sanitization and output escaping on the limit parameter. Authenticated users with Contributor-level access or above can inject arbitrary web scripts. Injected payloads execute in the browser of any user who visits an affected page. The issue is tracked under CWE-79 and is maintained by vendor wpmudev.

Critical Impact
Contributor-level accounts can persist JavaScript payloads that execute in the sessions of higher-privileged visitors, enabling session theft, forced administrative actions, and site defacement.

Affected Products

Forminator Forms plugin for WordPress, versions up to and including 1.42.0 (free/WordPress.org distribution)
WordPress sites where Contributor-or-above accounts can create or edit content using Forminator forms
Environments served without a content security policy that would block inline script execution

Discovery Timeline

2025-04-17 - CVE-2025-3487 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3487

Vulnerability Analysis

The Forminator plugin renders form output using front-end JavaScript loaders that consume attributes such as limit supplied through form configuration. When an authenticated user with at least Contributor privileges configures a form, the limit value is stored and later reflected into the DOM without adequate sanitization or output escaping. The front-end loader logic referenced in assets/js/front/front.loader.js and assets/js/front/front.multi.js incorporates these values during rendering. Because the plugin does not escape script-bearing input, an attacker can persist a payload that executes each time a page embedding the form is loaded. Any visitor authenticated at a higher privilege level runs the payload under their own session context, which enables account takeover paths and privileged actions performed on behalf of administrators.

Root Cause

The root cause is missing input sanitization and improper output escaping of the limit parameter along the form-rendering path. User-controlled input is trusted through storage and echoed into the browser context, satisfying the classic Stored XSS pattern defined by CWE-79.

Attack Vector

Exploitation requires an authenticated Contributor-or-above account and user interaction to view the affected page. The attacker configures a form containing a malicious limit value; the payload is stored server-side and delivered to any subsequent viewer. The stored payload's scope crosses trust boundaries because Contributors can influence content rendered to Editors and Administrators.

No verified proof-of-concept code is publicly available.
Refer to the vendor changeset and Wordfence advisory linked below for technical detail.

Detection Methods for CVE-2025-3487

Indicators of Compromise

Forminator form configurations containing <script> tags, on* event handlers, or javascript: URIs in the limit attribute
Unexpected outbound requests from browsers on wp-admin pages to attacker-controlled domains
New administrative users or altered role assignments created shortly after Contributor content edits
Modifications to WordPress options, theme files, or plugin settings that correlate with Contributor account activity

Detection Strategies

Review the wp_postmeta and Forminator-specific database tables for stored form fields containing HTML or JavaScript in the limit parameter
Enable WordPress audit logging to record form creation and updates performed by Contributor-level accounts
Deploy a web application firewall rule that flags requests containing script tags in Forminator form payloads
Monitor browser console errors and Content Security Policy violation reports on pages that render Forminator forms

Monitoring Recommendations

Alert on privilege escalation events, particularly new users assigned the administrator role
Track anomalous session activity for Editor and Administrator accounts after they view Contributor-authored content
Correlate plugin version inventory against the fixed release using regular scans of the WordPress plugin directory

How to Mitigate CVE-2025-3487

Immediate Actions Required

Upgrade the Forminator plugin to the version published in WordPress Changeset #3274844, which addresses the sanitization gap
Audit existing Forminator form configurations for injected script content in the limit parameter and remove any malicious entries
Review the Contributor, Author, and Editor user lists and disable accounts that are inactive or unfamiliar
Rotate credentials and session tokens for Administrator accounts that may have loaded compromised pages

Patch Information

The vendor addressed the vulnerability in the Forminator plugin release referenced by WordPress Changeset #3274844. Additional analysis is available in the Wordfence Vulnerability Report and the affected loader code paths are documented in the WordPress Forminator Loader JS and WordPress Forminator Multi JS references.

Workarounds

Temporarily restrict Contributor-and-above accounts from creating or editing Forminator forms until the patch is applied
Enforce a strict Content Security Policy that disallows inline scripts on pages that render Forminator forms
Place a WAF rule in front of wp-admin and public form endpoints to block script tags and event-handler attributes in the limit parameter

bash

# Example: update the Forminator plugin using WP-CLI
wp plugin update forminator
wp plugin get forminator --field=version