CVE-2025-31426: Sticky Radio Player XSS Vulnerability

CVE-2025-31426 Overview

CVE-2025-31426 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the Sticky Radio Player WordPress plugin (lbg-audio5-html5-shoutcast_sticky) developed by LambertGroup. This vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing attackers to inject malicious scripts that execute in the context of a victim's browser session.

Reflected XSS vulnerabilities in WordPress plugins pose significant risks as they can be leveraged to steal session cookies, redirect users to malicious sites, deface web content, or perform actions on behalf of authenticated users including administrators.

Critical Impact

Attackers can craft malicious URLs that, when clicked by WordPress administrators or users, execute arbitrary JavaScript in their browser context, potentially leading to session hijacking, credential theft, or unauthorized administrative actions.

Affected Products

• LambertGroup Sticky Radio Player (lbg-audio5-html5-shoutcast_sticky) versions through 3.4
• WordPress installations running the vulnerable plugin versions

Discovery Timeline

• 2025-06-09 - CVE-2025-31426 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-31426

Vulnerability Analysis

This vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The Sticky Radio Player plugin fails to properly sanitize user-controllable input before reflecting it back in the HTTP response, enabling Reflected XSS attacks.

In a Reflected XSS scenario, the malicious payload is typically embedded in a URL parameter. When a victim clicks the crafted link, the server includes the unsanitized payload in the response, causing the victim's browser to execute the attacker's JavaScript code. This attack requires social engineering to trick users into clicking the malicious link.

The vulnerability affects the plugin from its initial release through version 3.4, indicating a systemic input validation weakness in the plugin's codebase.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding within the Sticky Radio Player plugin. User-supplied data is reflected in the HTML response without proper sanitization or contextual encoding, allowing script injection. WordPress provides sanitization functions such as esc_html(), esc_attr(), and wp_kses() that should be applied to all user-controllable data before output, but these safeguards were not properly implemented.

Attack Vector

The attack vector for CVE-2025-31426 involves crafting a malicious URL containing JavaScript payload within a vulnerable parameter. The attacker must then convince a victim (typically a site administrator) to click the link through phishing emails, forum posts, or other social engineering techniques.

Once the victim accesses the malicious URL, the payload executes within their authenticated session context. For WordPress administrators, this could result in complete site compromise through actions such as creating new admin accounts, installing malicious plugins, or modifying site content.

The vulnerability is exploited through user interaction with a maliciously crafted URL. Technical details and proof-of-concept information can be found in the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-31426

Indicators of Compromise

• Suspicious URL parameters containing encoded script tags or JavaScript event handlers in requests to pages using the Sticky Radio Player plugin
• Unexpected outbound connections from user browsers to unknown domains after visiting the WordPress site
• User reports of unexpected redirects or pop-ups when accessing plugin-related functionality
• Web application firewall logs showing blocked XSS patterns targeting the lbg-audio5-html5-shoutcast_sticky plugin paths

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS payloads in URL parameters
• Monitor web server access logs for requests containing suspicious patterns such as <script>, javascript:, or encoded variants like %3Cscript%3E
• Deploy browser-based Content Security Policy (CSP) headers to restrict script execution sources and report violations
• Use WordPress security plugins that scan for known vulnerable plugin versions

Monitoring Recommendations

• Enable verbose logging for WordPress and specifically monitor requests to pages rendering the Sticky Radio Player
• Configure alerts for CSP violation reports that may indicate XSS exploitation attempts
• Monitor for unusual administrative activity following visits from external referrers
• Implement real-time alerting on WAF XSS rule triggers

How to Mitigate CVE-2025-31426

Immediate Actions Required

• Update the Sticky Radio Player plugin to the latest patched version immediately
• Review WordPress user accounts for any unauthorized administrator accounts that may have been created through exploitation
• Audit recent administrative actions in the WordPress activity log for suspicious changes
• Consider temporarily disabling the plugin if no patch is available

Patch Information

Site administrators should check for updates to the Sticky Radio Player plugin (lbg-audio5-html5-shoutcast_sticky) and apply any available security patches. Monitor the Patchstack Vulnerability Report for the latest remediation guidance from the vendor.

Workarounds

• Implement Content Security Policy (CSP) headers with strict script-src directives to mitigate XSS impact even if exploitation occurs
• Deploy a Web Application Firewall with XSS protection rules enabled to filter malicious requests
• Restrict administrative access to trusted IP addresses only to limit the attack surface
• Educate administrators about phishing risks and the dangers of clicking untrusted links while logged into WordPress

# Example Apache .htaccess CSP header configuration
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"
    Header set X-Content-Type-Options "nosniff"
    Header set X-XSS-Protection "1; mode=block"
</IfModule>