CVE-2026-1904: WordPress Accordion Plugin XSS Vulnerability

CVE-2026-1904 Overview

The Simple Wp colorfull Accordion plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the title parameter of the accordion shortcode. This security flaw affects all versions up to and including 1.0 and stems from insufficient input sanitization and output escaping. Authenticated attackers with Contributor-level access or higher can exploit this vulnerability to inject malicious web scripts into WordPress pages, which execute whenever any user accesses the compromised page.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in the context of other users' browsers, potentially leading to session hijacking, credential theft, or further compromise of the WordPress site.

Affected Products

• Simple Wp colorfull Accordion plugin for WordPress versions up to and including 1.0
• WordPress sites using the vulnerable accordion shortcode functionality
• All users with Contributor-level access or above on affected installations

Discovery Timeline

• February 14, 2026 - CVE-2026-1904 published to NVD
• February 18, 2026 - Last updated in NVD database

Technical Details for CVE-2026-1904

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists in the Simple Wp colorfull Accordion WordPress plugin due to improper handling of user-supplied input in the shortcode processing functionality. The plugin fails to adequately sanitize the title parameter before storing it in the database and does not properly escape the output when rendering the accordion content on the front end.

Stored XSS vulnerabilities are particularly dangerous because the malicious payload persists in the application's database and executes every time a user visits the affected page. In this case, an attacker with Contributor-level privileges can create or edit posts containing the vulnerable shortcode with a crafted title parameter containing JavaScript code. When any visitor—including administrators—views the page, the injected script executes in their browser context.

The scope of this vulnerability extends beyond the immediate WordPress installation, as indicated by the changed scope in the vulnerability assessment. This means successful exploitation can impact resources beyond the vulnerable component itself.

Root Cause

The root cause of CVE-2026-1904 is insufficient input sanitization and output escaping in the plugin's shortcode handler (CWE-79). The vulnerable code is located in Simple-Wp-colorfull-Accordion.php at approximately line 60, where the title parameter from the accordion shortcode is processed without proper validation or encoding.

WordPress provides built-in functions like sanitize_text_field(), esc_html(), and esc_attr() specifically to prevent XSS attacks, but the plugin fails to implement these security controls when handling the shortcode attributes before rendering them in the HTML output.

Attack Vector

The attack requires network access and authenticated access to the WordPress site with at least Contributor-level privileges. The exploitation flow follows these steps:

1. An attacker with Contributor access creates a new post or edits an existing one
2. The attacker inserts the accordion shortcode with a malicious title parameter containing JavaScript code
3. The malicious payload is stored in the WordPress database without proper sanitization
4. When any user (including administrators) views the published page, the unsanitized script executes in their browser
5. The attacker's script can perform actions such as stealing session cookies, redirecting users, or performing actions on behalf of the victim

The vulnerability can be triggered through the accordion shortcode by embedding JavaScript in the title attribute. For example, an attacker might include event handlers or script tags that bypass the insufficient sanitization. Detailed technical analysis is available in the WordPress Plugin Source Code and the Wordfence Vulnerability Report.

Detection Methods for CVE-2026-1904

Indicators of Compromise

• Presence of unexpected JavaScript code or event handlers within accordion shortcode title parameters in post content
• Unusual POST or database entries containing script tags, event handlers (e.g., onerror, onload), or encoded JavaScript payloads
• Browser console errors or unexpected script execution when viewing pages with accordion content
• User reports of unexpected redirects, pop-ups, or behavior when accessing pages containing accordions

Detection Strategies

• Search the WordPress database wp_posts table for accordion shortcodes containing suspicious patterns such as <script>, javascript:, or HTML event attributes
• Review WordPress user activity logs for Contributor or higher accounts creating posts with accordion shortcodes
• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Deploy web application firewall (WAF) rules to identify and log XSS payload patterns in post submissions

Monitoring Recommendations

• Enable detailed logging of post creation and modification activities, particularly for users with Contributor-level access
• Monitor for unusual patterns in page content modifications, especially involving shortcode parameters
• Implement real-time alerting for detected XSS patterns in submitted content using security plugins or WAF solutions
• Regularly audit installed plugins against vulnerability databases such as Wordfence Threat Intelligence

How to Mitigate CVE-2026-1904

Immediate Actions Required

• Remove or deactivate the Simple Wp colorfull Accordion plugin until a patched version is available
• Audit existing posts and pages for any accordion shortcodes with suspicious title parameters and remove malicious content
• Review user accounts with Contributor-level access or higher for any potentially compromised or unauthorized accounts
• Consider implementing additional access controls to restrict shortcode usage to trusted users only

Patch Information

As of the last NVD update on February 18, 2026, all versions of the Simple Wp colorfull Accordion plugin up to and including version 1.0 remain vulnerable. Site administrators should monitor the WordPress plugin repository and the Wordfence Vulnerability Report for updates on a security patch. Until an official fix is released, the plugin should be deactivated on production sites.

Workarounds

• Deactivate the Simple Wp colorfull Accordion plugin until a security update is available
• Implement a Web Application Firewall (WAF) with rules to block XSS payloads in POST requests
• Restrict Contributor-level user permissions or temporarily elevate the required role for creating posts with shortcodes
• Deploy Content Security Policy headers to mitigate the impact of any injected scripts

# Configuration example: Add CSP header in .htaccess to mitigate XSS
# Note: Adjust 'self' and allowed sources based on your site requirements
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"
</IfModule>