CVE-2025-8427: Beaver Builder Plugin XSS Vulnerability

CVE-2025-8427 Overview

CVE-2025-8427 is a Stored Cross-Site Scripting (XSS) vulnerability [CWE-79] in the Beaver Builder Plugin (Starter Version) for WordPress. The flaw affects all versions up to and including 2.9.2.1. It stems from insufficient input sanitization and output escaping on the auto_play parameter. Authenticated users with Contributor-level access or higher can inject arbitrary JavaScript into pages. The injected script executes in the browser of any visitor who accesses the affected page.

Critical Impact
Contributor-level attackers can inject persistent JavaScript that executes against site visitors and administrators, enabling session theft, forced actions, and privilege escalation chains.

Affected Products

Fastlinemedia Beaver Builder Plugin (Starter / Lite WordPress version)
All versions up to and including 2.9.2.1
WordPress sites allowing Contributor-level or higher accounts

Discovery Timeline

2025-10-23 - CVE-2025-8427 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-8427

Vulnerability Analysis

The Beaver Builder Plugin exposes an auto_play parameter that accepts user-controlled input without proper sanitization. When the parameter value is rendered back into the page, the plugin fails to escape output appropriately. An authenticated attacker with at least Contributor privileges can submit crafted content containing JavaScript payloads. The payload is stored in the WordPress database and executes whenever a user loads the affected page.

Stored XSS in a page builder context is particularly useful to attackers because the malicious content persists across sessions. The script executes in the context of the site origin, giving the attacker access to cookies, DOM content, and any administrative functionality the viewing user holds.

Root Cause

The root cause is a missing or insufficient escaping routine on the auto_play parameter. WordPress provides functions such as esc_attr(), esc_html(), and wp_kses() for safe output rendering. The vulnerable code path accepts the attribute value and emits it into page markup without applying these controls, violating the WordPress plugin development guidance for output escaping.

Attack Vector

Exploitation requires an authenticated session at Contributor level or above and user interaction to view the injected page. The attacker edits a page or post using the Beaver Builder interface, supplies a crafted auto_play value containing JavaScript, and saves the content. When any visitor, including an administrator, loads the page, the browser executes the injected script. The scope change in the CVSS vector reflects that the executed script affects a different security context than the vulnerable component.

No verified public exploit code is available for CVE-2025-8427. Technical details are documented in the Wordfence Vulnerability Report.

Detection Methods for CVE-2025-8427

Indicators of Compromise

Post or page meta records in wp_postmeta containing <script> tags, javascript: URIs, or event handlers such as onerror= and onload= within Beaver Builder module settings
Unexpected outbound requests from browsers loading pages built with Beaver Builder, especially to attacker-controlled domains
Contributor or Author accounts editing or creating pages outside their normal workflow pattern

Detection Strategies

Audit the WordPress database for Beaver Builder module settings containing the auto_play key and inspect values for HTML or JavaScript content
Review web server access logs for POST requests to admin-ajax.php and the WordPress REST API saving Beaver Builder content from low-privilege accounts
Deploy a Web Application Firewall rule to flag or block requests containing script tags in Beaver Builder parameters

Monitoring Recommendations

Monitor creation and privilege changes for Contributor, Author, and Editor accounts on WordPress sites running Beaver Builder
Enforce Content Security Policy headers and alert on CSP violation reports originating from pages that render Beaver Builder content
Track plugin version inventory across managed WordPress sites to confirm all installations are patched above 2.9.2.1

How to Mitigate CVE-2025-8427

Immediate Actions Required

Update the Beaver Builder Plugin to the latest version published after 2.9.2.1, as noted in the WP Beaver Builder Change Log
Audit all Contributor, Author, and Editor accounts and remove any that are inactive, unknown, or no longer required
Review existing Beaver Builder pages for injected scripts in the auto_play field and remove malicious content

Patch Information

Fastlinemedia addresses the vulnerability in a release following 2.9.2.1. Administrators should consult the WP Beaver Builder Change Log for the exact fixed version and apply the update through the WordPress plugin manager or by replacing plugin files directly.

Workarounds

Restrict Contributor-level and higher roles to trusted users until the patch is applied
Deploy a Web Application Firewall rule that blocks script tags and JavaScript event handlers in Beaver Builder parameter values
Apply a strict Content Security Policy that disallows inline script execution on pages rendered by the plugin

bash

# Verify installed Beaver Builder plugin version using WP-CLI
wp plugin get beaver-builder-lite-version --field=version

# Update the plugin to the latest available release
wp plugin update beaver-builder-lite-version

# List all users with Contributor role or higher for review
wp user list --role=contributor,author,editor --fields=ID,user_login,user_email,user_registered