CVE-2026-28113: Ultimate Learning Pro XSS Vulnerability

CVE-2026-28113 Overview

A Reflected Cross-Site Scripting (XSS) vulnerability has been identified in the Ultimate Learning Pro WordPress plugin (indeed-learning-pro) developed by azzaroco. This vulnerability allows attackers to inject malicious scripts into web pages viewed by other users, potentially leading to session hijacking, credential theft, and unauthorized actions on behalf of authenticated users.

Critical Impact

This reflected XSS vulnerability enables attackers to execute arbitrary JavaScript in victim browsers, potentially compromising user sessions, stealing sensitive data, and performing unauthorized actions within the WordPress learning management system.

Affected Products

• Ultimate Learning Pro (indeed-learning-pro) versions through 3.9.1
• WordPress sites running vulnerable versions of the plugin
• Users interacting with malicious links targeting the vulnerable plugin

Discovery Timeline

• 2026-03-05 - CVE-2026-28113 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28113

Vulnerability Analysis

This vulnerability stems from improper neutralization of user-supplied input during web page generation within the Ultimate Learning Pro plugin. The plugin fails to adequately sanitize or encode user input before reflecting it back in the HTML response, creating an injection point for malicious scripts. The vulnerability requires user interaction, as victims must click on a specially crafted malicious link to trigger the attack. Once executed, the injected script runs in the context of the victim's browser session with full access to cookies, session tokens, and the ability to manipulate page content.

Root Cause

The root cause of CVE-2026-28113 is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation). The Ultimate Learning Pro plugin does not properly sanitize or encode user-controlled input before including it in dynamically generated web pages. This allows attackers to inject HTML and JavaScript code that will be executed in the context of other users' browser sessions when they access specially crafted URLs.

Attack Vector

This is a network-based attack that requires no authentication but does require user interaction. An attacker crafts a malicious URL containing JavaScript payload targeting the vulnerable parameter in the Ultimate Learning Pro plugin. The attacker then distributes this link through phishing emails, social media, or other channels. When a victim clicks the link while authenticated to the WordPress site, the malicious script executes in their browser context, potentially allowing the attacker to steal session cookies, perform actions as the authenticated user, or redirect to phishing pages.

The vulnerability mechanism involves unsanitized user input being reflected directly in the HTML response. Attackers can exploit this by embedding JavaScript code in URL parameters, which when processed by the vulnerable plugin, gets rendered in the victim's browser without proper encoding. For detailed technical information about this vulnerability, refer to the Patchstack security advisory.

Detection Methods for CVE-2026-28113

Indicators of Compromise

• Suspicious URLs containing encoded JavaScript payloads in query parameters targeting the Ultimate Learning Pro plugin endpoints
• Web server logs showing requests with <script> tags, javascript: URIs, or event handlers (onerror, onload, onclick) in URL parameters
• User reports of unexpected browser behavior or redirects when accessing learning management features
• Detection of suspicious cookies being exfiltrated to external domains

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS payloads in requests targeting WordPress plugins
• Monitor HTTP request logs for patterns indicating XSS attempts such as encoded script tags and JavaScript event handlers
• Deploy browser-based Content Security Policy (CSP) headers to restrict script execution sources
• Utilize SentinelOne Singularity platform to detect anomalous browser behavior and script injection attempts

Monitoring Recommendations

• Enable detailed logging on WordPress and web server to capture full request URIs and parameters
• Configure SIEM alerts for requests containing common XSS signatures targeting the indeed-learning-pro plugin paths
• Monitor for unauthorized session activity that may indicate successful XSS exploitation
• Implement real-time alerting for requests blocked by WAF rules targeting this vulnerability

How to Mitigate CVE-2026-28113

Immediate Actions Required

• Update Ultimate Learning Pro plugin to a patched version when available from the vendor
• Implement a Web Application Firewall with XSS detection rules to filter malicious requests
• Apply Content Security Policy (CSP) headers to restrict inline script execution
• Educate users about the risks of clicking suspicious links, especially those targeting the learning management system
• Consider temporarily disabling the plugin if it is not critical to operations until a patch is available

Patch Information

Users should monitor the official Ultimate Learning Pro plugin repository and the Patchstack vulnerability database for patch announcements. Update to a version newer than 3.9.1 once a security fix is released. Always verify plugin updates through the official WordPress plugin directory or the vendor's official channels.

Workarounds

• Deploy a Web Application Firewall configured to block requests containing XSS patterns targeting the vulnerable plugin endpoints
• Implement strict Content Security Policy headers to prevent execution of inline scripts: Content-Security-Policy: default-src 'self'; script-src 'self';
• Restrict access to the WordPress admin area and learning management features to trusted IP ranges where feasible
• Temporarily disable the Ultimate Learning Pro plugin if the functionality is not essential until a patch is available

# WordPress .htaccess configuration to add basic XSS protection headers
<IfModule mod_headers.c>
    Header set X-XSS-Protection "1; mode=block"
    Header set X-Content-Type-Options "nosniff"
    Header set Content-Security-Policy "default-src 'self'; script-src 'self';"
</IfModule>