CVE-2025-14725: Internal Link Builder WordPress XSS Flaw

CVE-2025-14725 Overview

The Internal Link Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting (XSS) via admin settings in all versions up to, and including, 1.0. The vulnerability stems from insufficient input sanitization and output escaping within the plugin's administrative interface. This security flaw enables authenticated attackers with administrator-level permissions and above to inject arbitrary web scripts into pages that will execute whenever a user accesses an injected page.

Critical Impact

This vulnerability allows malicious administrators to inject persistent scripts that execute in the context of other users' browsers, potentially leading to session hijacking, credential theft, or further compromise of WordPress installations. The vulnerability specifically affects multi-site installations and installations where unfiltered_html has been disabled.

Affected Products

• Internal Link Builder plugin for WordPress version 1.0 and below
• WordPress multi-site installations using the affected plugin
• WordPress installations with unfiltered_html capability disabled

Discovery Timeline

• 2026-01-14 - CVE CVE-2025-14725 published to NVD
• 2026-01-14 - Last updated in NVD database

Technical Details for CVE-2025-14725

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists within the admin settings functionality of the Internal Link Builder plugin. The root issue lies in the plugin's failure to properly sanitize user-supplied input and escape output when rendering administrative settings pages. When an administrator saves settings containing malicious JavaScript code, the payload is stored in the database and subsequently rendered without proper escaping, causing the script to execute in the browsers of users who access the affected pages.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), which is one of the most common web application security weaknesses. While the attack requires administrator-level access to exploit, the stored nature of the XSS means the malicious payload persists and can affect multiple users over time.

Root Cause

The vulnerability originates from improper handling of user input within the InternalLinkBuilder.php file, specifically around line 133 where admin settings are processed. The plugin fails to implement adequate input sanitization using WordPress security functions such as sanitize_text_field() or esc_attr() before storing data, and neglects proper output escaping using functions like esc_html() or wp_kses() when displaying the settings back to users.

Attack Vector

The attack requires an authenticated user with administrator-level privileges to access the plugin's settings page and inject malicious JavaScript code into one or more settings fields. Once saved, the malicious script is stored in the WordPress database. When any user (including other administrators) accesses a page that renders the poisoned settings, the injected JavaScript executes within their browser session.

The attack is network-based and requires high privileges to execute, but the changed scope means the impact can extend beyond the vulnerable component to affect other users and potentially the broader WordPress installation. This is particularly concerning in multi-site environments where a compromised site administrator could potentially impact users across the network.

Detection Methods for CVE-2025-14725

Indicators of Compromise

• Unexpected JavaScript code or HTML tags present in Internal Link Builder plugin settings stored in the wp_options database table
• Unusual admin activity logs showing modifications to the Internal Link Builder plugin settings
• Browser developer console errors or unexpected script execution when accessing plugin settings pages
• Reports from users experiencing unexpected redirects, pop-ups, or behavior anomalies when browsing the WordPress site

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Monitor WordPress admin audit logs for suspicious modifications to plugin settings, particularly those containing script tags or JavaScript event handlers
• Deploy web application firewalls (WAF) with XSS detection rules to identify malicious payload injection attempts
• Perform regular code reviews and security scans of plugin settings stored in the database

Monitoring Recommendations

• Enable WordPress debug logging and review logs for unusual activity related to the Internal Link Builder plugin
• Configure SentinelOne to monitor for suspicious JavaScript execution patterns and browser-based attack indicators
• Implement database integrity monitoring to detect unauthorized modifications to plugin settings
• Set up alerts for admin settings changes, especially those containing special characters commonly used in XSS payloads (<, >, script, onerror, onclick)

How to Mitigate CVE-2025-14725

Immediate Actions Required

• Review and audit all Internal Link Builder plugin settings for any suspicious or unexpected content containing JavaScript or HTML tags
• Temporarily disable the Internal Link Builder plugin until a patched version is available or alternative mitigations are in place
• Restrict administrator access to only trusted users and review recent admin activity logs for signs of compromise
• Implement Content Security Policy headers to mitigate the impact of any stored XSS payloads

Patch Information

As of the publication date, administrators should check the WordPress Plugin Repository and Wordfence Vulnerability Report for updates regarding patched versions of the Internal Link Builder plugin. Update to the latest version as soon as a security fix becomes available.

Workarounds

• Disable the Internal Link Builder plugin until a patched version is released
• Implement strict Content Security Policy (CSP) headers that disallow inline scripts: script-src 'self'
• Use WordPress security plugins such as Wordfence to add additional XSS protection layers
• Limit administrator access to trusted users only and enable two-factor authentication for all admin accounts
• Consider using alternative internal linking plugins that have been recently audited for security vulnerabilities

# Add Content Security Policy header to wp-config.php or .htaccess
# Apache .htaccess example:
Header set Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-eval'; style-src 'self' 'unsafe-inline';"

# Or add to WordPress theme's functions.php:
# add_action('send_headers', function() {
#     header("Content-Security-Policy: default-src 'self'; script-src 'self';");
# });