CVE-2026-3997: Text Toggle WordPress Plugin XSS Vulnerability

CVE-2026-3997 Overview

The Text Toggle plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the 'title' shortcode attribute of the [tt_part] and [tt] shortcodes. This vulnerability affects all versions up to and including 1.1 and allows authenticated attackers with Contributor-level access or above to inject arbitrary web scripts that execute when users access the compromised pages.

Critical Impact

Authenticated attackers can inject malicious JavaScript that persists in WordPress pages, potentially stealing user credentials, hijacking admin sessions, or redirecting visitors to malicious sites.

Affected Products

• Text Toggle plugin for WordPress versions up to and including 1.1
• WordPress installations using affected Text Toggle plugin versions

Discovery Timeline

• 2026-03-21 - CVE CVE-2026-3997 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-3997

Vulnerability Analysis

This vulnerability stems from insufficient input sanitization and output escaping on user-supplied shortcode attributes in the Text Toggle WordPress plugin. The avp_texttoggle_part_shortcode() function extracts the 'title' attribute from shortcode inputs and concatenates it directly into HTML output without performing any sanitization or escaping operations.

The vulnerability manifests in two distinct contexts within the code: within an HTML attribute context (title="...") on line 116 of avp-texttoggle.php, and within HTML content on line 119. This dual-context exposure amplifies the attack surface, as attackers can exploit either or both insertion points.

Notably, while the plugin developers implemented proper validation for the 'class' attribute using ctype_alnum(), they failed to apply any sanitization whatsoever to the 'title' attribute. This inconsistent security implementation creates a clear exploitation pathway.

Root Cause

The root cause is a classic input validation failure where the 'title' attribute value is directly embedded into HTML output without using WordPress's built-in escaping functions such as esc_attr() for attribute contexts or esc_html() for content contexts. The code trusts user-supplied input implicitly, violating fundamental secure coding principles for web applications.

Attack Vector

An attacker with Contributor-level WordPress access can craft a malicious shortcode payload that includes double-quote characters to break out of the title attribute context. By escaping the attribute boundary, the attacker can inject arbitrary HTML attributes including event handlers like onmouseover, onclick, or onerror that execute JavaScript code.

The attack vector is network-based and requires low-privilege authentication (Contributor role), but does not require user interaction for the exploit payload to be delivered—the malicious script executes automatically when any user views the injected page. The impact extends beyond the vulnerable site due to the changed scope, potentially affecting users' browsers in ways that impact other origins.

The vulnerable code paths can be examined in the WordPress Text Toggle source code at lines 116 and 119. For detailed technical analysis, refer to the Wordfence Vulnerability Analysis.

Detection Methods for CVE-2026-3997

Indicators of Compromise

• Presence of [tt] or [tt_part] shortcodes with suspicious title attributes containing special characters like double quotes, angle brackets, or JavaScript event handlers
• User-submitted content containing encoded payloads such as ", ", or URL-encoded characters in shortcode attributes
• WordPress posts or pages created by Contributor-level users containing Text Toggle shortcodes with unusual formatting

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect XSS patterns in WordPress shortcode attributes
• Deploy browser-based Content Security Policy (CSP) headers to mitigate script execution from inline event handlers
• Enable WordPress audit logging to track shortcode usage and content modifications by lower-privileged users
• Scan WordPress database for existing [tt] and [tt_part] shortcodes with potentially malicious title attribute values

Monitoring Recommendations

• Monitor WordPress user activity logs for unusual content creation patterns by Contributor-level accounts
• Implement real-time alerting for JavaScript execution from unexpected inline event handlers
• Review WordPress plugin update status and ensure Text Toggle plugin receives security patches when available

How to Mitigate CVE-2026-3997

Immediate Actions Required

• Audit all existing WordPress posts and pages for potentially malicious [tt] or [tt_part] shortcodes and sanitize or remove suspicious content
• Consider temporarily disabling the Text Toggle plugin until a patched version becomes available
• Restrict Contributor-level access to trusted users only, or temporarily elevate posting permissions to Editor-level
• Implement Content Security Policy headers to restrict inline script execution

Patch Information

At the time of publication, no official patch has been released for this vulnerability. Monitor the WordPress Plugin Directory and the plugin's official channels for security updates. When available, update the Text Toggle plugin immediately to a version newer than 1.1.

For the latest vulnerability status and patch availability, check the Wordfence Vulnerability Analysis.

Workarounds

• Implement a custom WordPress filter to sanitize the 'title' attribute in Text Toggle shortcodes using esc_attr() before output
• Use a security plugin like Wordfence to add WAF rules blocking XSS patterns in shortcode processing
• Temporarily remove or deactivate the Text Toggle plugin from production WordPress installations
• Consider replacing the plugin with an alternative that implements proper input sanitization

# WordPress database audit for suspicious shortcodes
# Run this query to identify potentially malicious Text Toggle shortcodes
wp db query "SELECT ID, post_title, post_author FROM wp_posts WHERE post_content LIKE '%[tt%title=%\"%' OR post_content LIKE '%[tt_part%title=%\"%'"

# Disable the plugin via WP-CLI as a temporary mitigation
wp plugin deactivate text-toggle