CVE-2025-13738: Easy Table of Contents WordPress XSS Flaw

CVE-2025-13738 Overview

The Easy Table of Contents plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the ez-toc shortcode functionality. All versions up to and including 2.0.78 are affected due to insufficient input sanitization and output escaping on user-supplied attributes. This vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts into pages, which execute whenever a user accesses the compromised page.

Critical Impact

Authenticated attackers can inject persistent malicious JavaScript that executes in the browsers of all users viewing affected pages, potentially leading to session hijacking, credential theft, or malware distribution.

Affected Products

• Easy Table of Contents WordPress Plugin versions up to and including 2.0.78
• WordPress installations with the Easy Table of Contents plugin enabled
• Sites allowing contributor-level or higher user access

Discovery Timeline

• 2026-02-19 - CVE CVE-2025-13738 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2025-13738

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists within the ez-toc shortcode processing logic of the Easy Table of Contents plugin. The core issue stems from the plugin's failure to properly sanitize and escape user-supplied attribute values before rendering them in the HTML output. When an authenticated user with at least contributor-level privileges creates or edits a post containing the malicious shortcode, the unsanitized payload is stored in the database and subsequently executed in the browsers of all visitors who view the affected page.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), a common weakness pattern in web applications where untrusted data is included in web page output without proper encoding.

Root Cause

The root cause of this vulnerability lies in the class-eztoc-post.php file, specifically in the shortcode handling logic. The plugin accepts user-supplied attributes through the ez-toc shortcode but fails to implement adequate input validation and output escaping mechanisms. When these attributes are processed and rendered into the page HTML, malicious JavaScript code embedded within the attributes is executed in the user's browser context.

The vulnerable code path can be examined in the WordPress Plugin Code Reference.

Attack Vector

The attack is network-based and requires authenticated access to the WordPress installation with contributor-level privileges or higher. An attacker can exploit this vulnerability by:

1. Logging into the WordPress site with contributor-level credentials
2. Creating or editing a post containing the ez-toc shortcode with malicious attribute values
3. Publishing or submitting the post for review
4. Waiting for users to view the affected page, triggering script execution

The vulnerability exploits insufficient sanitization of shortcode attributes. When a user views a page containing the malicious shortcode, the injected JavaScript executes within the context of the victim's browser session, enabling the attacker to steal cookies, redirect users, or perform actions on behalf of the victim.

For detailed technical analysis, see the Wordfence Vulnerability Report.

Detection Methods for CVE-2025-13738

Indicators of Compromise

• Unusual JavaScript code embedded in post content containing ez-toc shortcodes
• Posts with suspicious or obfuscated attribute values in the ez-toc shortcode
• Unexpected script execution or redirects when viewing pages with table of contents
• Browser console errors indicating blocked or suspicious script activity

Detection Strategies

• Review WordPress posts and pages for ez-toc shortcodes with unusual attribute values
• Monitor web application firewall logs for XSS payload patterns in POST requests to wp-admin
• Implement content security policies to detect and block unauthorized inline scripts
• Use WordPress security plugins to scan for known XSS patterns in stored content

Monitoring Recommendations

• Enable verbose logging for WordPress post creation and editing activities
• Monitor for contributor-level users creating posts with complex shortcode structures
• Configure web application firewalls to alert on common XSS payload signatures
• Regularly audit user accounts with contributor-level access or above

How to Mitigate CVE-2025-13738

Immediate Actions Required

• Update the Easy Table of Contents plugin to version 2.0.79 or later immediately
• Review all posts containing ez-toc shortcodes for suspicious content
• Temporarily restrict contributor-level access if immediate patching is not possible
• Implement a web application firewall to filter malicious XSS payloads

Patch Information

The vulnerability has been addressed in versions newer than 2.0.78. The fix implements proper input sanitization and output escaping for user-supplied shortcode attributes. The patch details can be reviewed in the WordPress Change Set Details.

Site administrators should update through the WordPress plugin dashboard or download the latest version from the WordPress plugin repository.

Workarounds

• Temporarily disable the Easy Table of Contents plugin until patching is complete
• Restrict user registration and limit contributor-level account creation
• Implement Content Security Policy headers to mitigate script execution
• Use a WAF rule to block requests containing potential XSS payloads in shortcode attributes

# WordPress CLI command to update the plugin
wp plugin update easy-table-of-contents

# Verify the installed version
wp plugin get easy-table-of-contents --field=version

# Temporarily deactivate if patching is delayed
wp plugin deactivate easy-table-of-contents