CVE-2026-24564: Textmetrics webtexttool XSS Vulnerability

CVE-2026-24564 Overview

CVE-2026-24564 is a Cross-Site Scripting (XSS) vulnerability affecting the Textmetrics (webtexttool) WordPress plugin. The vulnerability stems from improper neutralization of script-related HTML tags in web page content, classified under CWE-80 (Improper Neutralization of Script-Related HTML Tags in a Web Page). This weakness enables attackers to inject malicious code through arbitrary shortcode execution, potentially compromising user sessions and website integrity.

Critical Impact

Attackers with high-privileged access can inject malicious scripts that execute in the context of victim browsers, potentially leading to session hijacking, credential theft, and unauthorized actions on behalf of authenticated users.

Affected Products

• Textmetrics WordPress Plugin versions through 3.6.3
• WordPress installations running vulnerable Textmetrics plugin versions
• Websites utilizing the webtexttool functionality

Discovery Timeline

• 2026-01-23 - CVE-2026-24564 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-24564

Vulnerability Analysis

This vulnerability exists due to insufficient input validation and output encoding within the Textmetrics WordPress plugin. The plugin fails to properly sanitize script-related HTML tags before rendering them in web pages, creating an avenue for code injection attacks.

The attack requires high privileges (administrator or editor-level access) and user interaction to trigger, which limits the overall exploitability. However, once successfully exploited, the injected code executes within the security context of the victim's browser session, allowing attackers to perform actions on behalf of the user, steal sensitive information, or redirect users to malicious websites.

Root Cause

The root cause of CVE-2026-24564 is the failure to implement proper input sanitization and output encoding for user-controlled data processed through WordPress shortcodes. The Textmetrics plugin does not adequately filter or escape HTML tags with script-related attributes before including them in page output, violating secure coding practices for handling untrusted input in web applications.

Attack Vector

The vulnerability is exploitable over the network without requiring local access to the target system. An attacker with high-level privileges can craft malicious shortcode content containing script-related HTML tags. When a victim user views a page containing the malicious content, the injected script executes in their browser context.

The attack flow involves:

1. An authenticated attacker with elevated privileges creates or modifies content containing malicious shortcodes
2. The vulnerable plugin processes the shortcode without proper sanitization
3. Malicious HTML/script content is rendered in the page output
4. Victim users visiting the affected page execute the injected code

For detailed technical information about this vulnerability, refer to the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2026-24564

Indicators of Compromise

• Unusual or obfuscated HTML content within WordPress posts, pages, or shortcode parameters
• Unexpected shortcode entries in database content that contain script tags or event handlers
• Browser console errors or warnings related to script execution from unexpected sources
• User reports of suspicious redirects or pop-ups when viewing specific pages

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block unauthorized script execution
• Review WordPress database content for suspicious shortcode patterns containing HTML tags like <script>, <iframe>, or event handlers
• Monitor web application firewall (WAF) logs for XSS attack patterns targeting shortcode parameters
• Conduct regular security audits of WordPress plugin configurations and stored content

Monitoring Recommendations

• Enable detailed logging for WordPress content modifications, particularly shortcode-related changes
• Configure real-time alerting for web application firewall XSS signature matches
• Implement browser-based monitoring solutions to detect unexpected script execution on client side
• Review plugin activity logs for anomalous content creation or modification patterns

How to Mitigate CVE-2026-24564

Immediate Actions Required

• Update the Textmetrics (webtexttool) plugin to a patched version when available from the vendor
• Temporarily disable the Textmetrics plugin if a patch is not yet available and the functionality is not critical
• Review all existing content created using the plugin for signs of malicious injection
• Implement Web Application Firewall (WAF) rules to filter XSS attack patterns

Patch Information

Organizations should monitor the official WordPress plugin repository and the Patchstack vulnerability database for updates regarding patches for Textmetrics versions 3.6.3 and earlier. Until an official patch is released, implementing compensating controls is strongly recommended.

Workarounds

• Restrict plugin access to only the most trusted administrator accounts
• Implement Content Security Policy headers to mitigate the impact of successful XSS attacks
• Use WordPress security plugins that provide input filtering and output encoding capabilities
• Conduct manual review of all content created through the Textmetrics plugin shortcode functionality

# Example Content Security Policy header configuration for Apache
# Add to .htaccess or virtual host configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"

# For Nginx, add to server block
# add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';";