CVE-2026-57754 Overview
CVE-2026-57754 is a stored Cross-Site Scripting (XSS) vulnerability in the Livemesh Addons for WPBakery Page Builder WordPress plugin. The flaw affects all versions up to and including 3.9.4. Authenticated users with Contributor-level privileges can inject malicious JavaScript that executes in the browsers of other users, including administrators, when the affected content is rendered. The issue is tracked under CWE-79 and stems from insufficient input sanitization and output escaping within plugin shortcodes or widget parameters.
Critical Impact
A Contributor-level account can inject persistent JavaScript that executes in higher-privileged users' sessions, enabling session theft, administrative action forgery, or redirection to malicious infrastructure.
Affected Products
- Livemesh Addons for WPBakery Page Builder plugin for WordPress
- Versions <= 3.9.4
- WordPress sites permitting Contributor-level registration or accounts
Discovery Timeline
- 2026-07-02 - CVE-2026-57754 published to the National Vulnerability Database (NVD)
- 2026-07-02 - Last updated in NVD database
Technical Details for CVE-2026-57754
Vulnerability Analysis
The vulnerability is a stored XSS flaw introduced through plugin components that accept user-supplied content without proper sanitization. Contributors in WordPress can create draft posts and use shortcodes or page-builder elements exposed by the Livemesh Addons plugin. When one of these elements accepts attributes or content without escaping, an attacker can embed JavaScript payloads that persist in the database.
Once an editor or administrator previews or publishes the submitted content, the injected script executes in their authenticated browser context. This crosses a privilege boundary, which is reflected in the CVSS scope-changed rating for the vulnerability. The scripts run with the victim's session cookies and can perform any action the victim is authorized to perform.
Root Cause
The root cause is missing or incomplete output escaping in one or more shortcode handlers within the Livemesh Addons plugin. WordPress provides sanitization helpers such as esc_attr(), esc_html(), and wp_kses_post(), but the plugin fails to apply these consistently to Contributor-supplied inputs before rendering them into the DOM.
Attack Vector
An attacker must first obtain a Contributor account, either through open registration or credential compromise. The attacker then creates a draft post containing a Livemesh shortcode or builder element with a JavaScript payload injected into a vulnerable attribute. When an administrator or editor reviews the submission, the payload executes in their session context. User interaction from the higher-privileged victim is required, which corresponds to the UI:R designation in the CVSS vector.
The vulnerability is described in the Patchstack WordPress XSS Vulnerability advisory. No public proof-of-concept exploit code is available in verified sources.
Detection Methods for CVE-2026-57754
Indicators of Compromise
- Draft or pending posts authored by Contributor accounts containing <script>, javascript:, or event-handler strings such as onerror= and onload= within shortcode attributes.
- Outbound requests from administrator browsers to unfamiliar domains shortly after previewing Contributor-submitted content.
- Unexpected creation of administrative users, plugin installs, or option changes following content review activity.
Detection Strategies
- Query the wp_posts table for post content containing Livemesh shortcodes combined with script tags or JavaScript URI schemes.
- Enable and review WordPress audit logs for suspicious edits or admin actions correlated with Contributor draft submissions.
- Deploy a Web Application Firewall (WAF) rule set that inspects POST bodies to wp-admin/post.php and admin-ajax.php for XSS payloads targeting page-builder attributes.
Monitoring Recommendations
- Monitor for new user registrations at the Contributor role and correlate with unusual post drafts.
- Alert on administrator sessions that generate anomalous XHR or fetch() requests to the REST API after previewing content.
- Track plugin file integrity and confirm that Livemesh Addons versions match the approved patched release.
How to Mitigate CVE-2026-57754
Immediate Actions Required
- Update the Livemesh Addons for WPBakery Page Builder plugin to a version later than 3.9.4 as soon as the vendor releases a patched build.
- Audit all existing Contributor accounts and remove or downgrade accounts that are not actively required.
- Review Contributor-authored drafts and pending posts for embedded scripts before any editor or administrator previews them.
Patch Information
Refer to the Patchstack advisory for the current fixed version and vendor guidance. Apply the update across all environments, including staging sites that share administrator sessions.
Workarounds
- Disable open user registration or restrict the default role to Subscriber until the plugin is patched.
- Deactivate the Livemesh Addons for WPBakery Page Builder plugin if it is not required for production functionality.
- Enforce a Content Security Policy (CSP) that restricts inline script execution on WordPress admin pages to limit payload impact.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
