CVE-2025-12803: Bold Page Builder WordPress XSS Vulnerability

CVE-2025-12803 Overview

The Bold Page Builder plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the bt_bb_tabs shortcode functionality. All versions up to and including 5.5.1 are affected due to insufficient input sanitization and output escaping on user-supplied attributes. This vulnerability allows authenticated attackers with contributor-level access or above to inject arbitrary web scripts into WordPress pages that execute whenever a user accesses an injected page.

Critical Impact

Authenticated attackers can persistently inject malicious JavaScript that executes in the context of any user viewing affected pages, potentially leading to session hijacking, credential theft, or further site compromise.

Affected Products

• Bold Page Builder WordPress plugin versions up to and including 5.5.1
• WordPress sites utilizing the bt_bb_tabs shortcode functionality
• Any WordPress installation with contributor-level or higher user accounts

Discovery Timeline

• 2026-02-07 - CVE-2025-12803 published to NVD
• 2026-02-09 - Last updated in NVD database

Technical Details for CVE-2025-12803

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability (CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page) occurs within the Bold Page Builder plugin's bt_bb_tabs shortcode processing. The vulnerability stems from the plugin's failure to properly sanitize and escape user-controlled input when rendering tab elements on the page.

When a user with contributor-level privileges creates or edits content using the bt_bb_tabs shortcode, they can inject malicious attributes that bypass the plugin's insufficient input validation. The injected payload is stored in the WordPress database and subsequently rendered without proper output escaping, causing the malicious script to execute in the browsers of all users who view the affected page.

The attack requires network access and low privileges (contributor-level account), but no user interaction is needed beyond viewing the compromised page. The vulnerability has a changed scope, meaning the exploitation can impact resources beyond the vulnerable component itself.

Root Cause

The root cause lies in inadequate input sanitization and missing output escaping within the bt_bb_tabs.php file. The shortcode handler accepts user-supplied attributes and incorporates them into the rendered HTML output without properly encoding special characters or validating attribute values against an allowlist. This allows attackers to break out of attribute contexts and inject executable JavaScript code.

Attack Vector

The attack vector is network-based, requiring an authenticated user with at least contributor-level access to the WordPress site. The attacker leverages the page builder's shortcode system to craft a malicious bt_bb_tabs element containing JavaScript payloads within shortcode attributes.

The vulnerability manifests in the tab element rendering function where user-supplied attributes are processed. Attackers can inject event handlers or script elements that execute when the page loads. For detailed technical analysis of the vulnerable code path, refer to the WordPress Plugin Code Reference in the WordPress plugin repository.

Detection Methods for CVE-2025-12803

Indicators of Compromise

• Presence of unexpected JavaScript code within post content containing bt_bb_tabs shortcodes
• Suspicious event handlers (e.g., onerror, onload, onclick) embedded in page builder element attributes
• User reports of unexpected browser behavior, pop-ups, or redirects when viewing specific pages
• Web application firewall logs showing XSS signature matches on pages using Bold Page Builder

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Deploy web application firewall rules to monitor for XSS payloads in shortcode attributes
• Audit WordPress posts and pages for suspicious content patterns within [bt_bb_tabs] shortcode blocks
• Review user activity logs for contributors making unusual edits to page content

Monitoring Recommendations

• Enable detailed logging for WordPress post modifications, particularly those involving page builder shortcodes
• Configure SentinelOne Singularity to monitor for suspicious JavaScript execution patterns on web servers
• Implement real-time alerting for changes to pages containing Bold Page Builder elements
• Monitor outbound network connections from the web server for potential data exfiltration

How to Mitigate CVE-2025-12803

Immediate Actions Required

• Update Bold Page Builder plugin to a version newer than 5.5.1 that addresses this vulnerability
• Review and audit all existing pages using bt_bb_tabs shortcodes for potentially malicious content
• Temporarily restrict contributor-level access until the patch is applied
• Implement Content Security Policy headers to mitigate the impact of any existing injected scripts

Patch Information

Organizations should update the Bold Page Builder plugin to the latest available version through the WordPress plugin update mechanism. Review the Wordfence Vulnerability Report for the most current patching guidance. Verify the update was successful by checking the plugin version in the WordPress admin dashboard under Plugins.

Workarounds

• Disable the Bold Page Builder plugin entirely until a patch can be applied
• Remove contributor-level access for untrusted users to prevent exploitation
• Implement a Web Application Firewall (WAF) rule to filter XSS patterns in page builder attributes
• Use WordPress security plugins to scan for and quarantine suspicious shortcode content

# Configuration example
# WordPress wp-config.php - Add security headers via PHP
# Add to your theme's functions.php or a security plugin

# Implement Content Security Policy to mitigate XSS impact
# Add this to your .htaccess file:
Header set Content-Security-Policy "script-src 'self'; object-src 'none';"

# Or add via WordPress functions.php:
# add_action('send_headers', function() {
#     header("Content-Security-Policy: script-src 'self'; object-src 'none';");
# });