CVE-2026-25451: Bold Page Builder Stored XSS Vulnerability

CVE-2026-25451 Overview

A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the Bold Page Builder WordPress plugin. This vulnerability stems from improper neutralization of input during web page generation (CWE-79), allowing attackers to inject malicious scripts that persist in the application and execute in victims' browsers.

The Bold Page Builder plugin, developed by boldthemes, fails to properly sanitize user-supplied input before rendering it in web pages. This allows authenticated attackers to inject arbitrary JavaScript code that gets stored on the server and executed whenever users view the affected content.

Critical Impact

Authenticated attackers can inject persistent malicious scripts into WordPress pages, potentially leading to session hijacking, credential theft, and unauthorized actions on behalf of site visitors.

Affected Products

• Bold Page Builder plugin versions through 5.6.4
• WordPress installations running vulnerable Bold Page Builder versions

Discovery Timeline

• 2026-02-19 - CVE-2026-25451 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-25451

Vulnerability Analysis

This Stored XSS vulnerability in Bold Page Builder represents a significant security risk for WordPress sites using this popular page building plugin. Unlike Reflected XSS attacks that require victims to click malicious links, Stored XSS persists on the server, executing automatically when users access the compromised content.

The vulnerability allows attackers to bypass input validation mechanisms and inject malicious payloads that become permanently embedded in page content. When legitimate users—including administrators—view these pages, the injected scripts execute within their browser context with full access to the page DOM, session cookies, and other sensitive data.

Root Cause

The root cause of CVE-2026-25451 is insufficient input sanitization within the Bold Page Builder plugin's content handling mechanisms. The plugin fails to properly escape or filter user-provided content before storing it in the database and rendering it on web pages. This violates the fundamental security principle of treating all user input as potentially malicious.

WordPress plugins that handle rich content creation, like page builders, must implement robust output encoding and input validation to prevent XSS attacks. The Bold Page Builder's failure to do so allows HTML and JavaScript injection through builder elements.

Attack Vector

The attack requires an authenticated user with content creation privileges to inject malicious scripts through the Bold Page Builder interface. Once the payload is stored, it executes in the browsers of any user viewing the affected page, including site administrators with elevated privileges.

A typical attack scenario involves injecting JavaScript code that captures session cookies, performs unauthorized actions, redirects users to phishing sites, or downloads malware. The persistent nature of Stored XSS makes it particularly dangerous as it can affect multiple victims over time without requiring social engineering for each target.

Detection Methods for CVE-2026-25451

Indicators of Compromise

• Presence of unexpected <script> tags or JavaScript event handlers within Bold Page Builder content blocks
• Unusual JavaScript code in page source that was not intentionally added by content creators
• User reports of unexpected browser behavior, redirects, or pop-ups when viewing specific pages
• Abnormal outbound network requests from client browsers to external domains

Detection Strategies

• Implement Web Application Firewalls (WAF) configured to detect and block common XSS payloads
• Deploy Content Security Policy (CSP) headers to restrict script execution to trusted sources
• Conduct regular security scans of WordPress installations using vulnerability scanners
• Review page builder content for suspicious code patterns and unauthorized modifications

Monitoring Recommendations

• Enable comprehensive logging for WordPress content creation and modification events
• Monitor for unusual patterns in Bold Page Builder element updates or bulk content changes
• Configure alerts for CSP violation reports indicating blocked script execution attempts
• Track plugin file integrity to detect unauthorized modifications to Bold Page Builder files

How to Mitigate CVE-2026-25451

Immediate Actions Required

• Update Bold Page Builder to a patched version when available from boldthemes
• Audit existing page content created with Bold Page Builder for suspicious scripts or code
• Implement strict Content Security Policy headers to limit script execution
• Consider temporarily restricting Bold Page Builder access to trusted administrators only

Patch Information

Website administrators should monitor the Patchstack WordPress Vulnerability Report for updates regarding patches and remediation guidance. Update the Bold Page Builder plugin to a version newer than 5.6.4 once a security patch is released by boldthemes.

Workarounds

• Implement server-side input filtering to sanitize HTML content submitted through the page builder
• Deploy a Web Application Firewall with XSS protection rules enabled
• Configure Content Security Policy headers to restrict inline script execution using script-src 'self'
• Limit Bold Page Builder editing capabilities to highly trusted users only until a patch is available

# Example Content Security Policy header configuration for Apache
# Add to .htaccess or Apache configuration

Header always set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';"

# For nginx, add to server block:
# add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';" always;