CVE-2026-3766: Pharmacy Management System XSS Vulnerability

CVE-2026-3766 Overview

A Cross-Site Scripting (XSS) vulnerability has been discovered in SourceCodester Web-based Pharmacy Product Management System version 1.0. This security flaw affects the edit-profile.php file, where improper handling of the fullname argument allows attackers to inject malicious scripts. The vulnerability can be exploited remotely by authenticated users, enabling them to execute arbitrary JavaScript code in the context of other users' browsers.

Critical Impact

Attackers can inject malicious scripts through the fullname parameter in edit-profile.php, potentially leading to session hijacking, credential theft, and unauthorized actions on behalf of legitimate users within the pharmacy management system.

Affected Products

• SourceCodester Web-based Pharmacy Product Management System 1.0
• senior-walter web-based_pharmacy_product_management_system

Discovery Timeline

• 2026-03-08 - CVE-2026-3766 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3766

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw exists in the edit-profile.php file of the Web-based Pharmacy Product Management System, which fails to properly sanitize user-supplied input in the fullname parameter before rendering it in the web page.

When a user updates their profile information, the application accepts input through the fullname field without adequate validation or encoding. This allows an attacker to inject HTML or JavaScript code that will be executed when the profile information is displayed to other users or administrators viewing the system.

The attack requires network access and a low-privileged authenticated user account. User interaction is required for successful exploitation, as a victim must view the page containing the malicious payload. The impact is primarily to the integrity of the web application's output, enabling script injection attacks.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the edit-profile.php script. The application directly incorporates user-supplied data from the fullname parameter into the HTML response without sanitizing special characters or applying proper output encoding. This allows attackers to break out of the intended data context and inject executable script content.

Attack Vector

The attack is initiated remotely over the network. An authenticated attacker with low privileges can manipulate the fullname argument when editing their profile. By injecting specially crafted JavaScript or HTML code into this field, the attacker can store malicious content in the application's database. When other users, particularly administrators, view the attacker's profile or any page displaying the manipulated fullname, the malicious script executes in their browser session.

This stored XSS attack can be leveraged to steal session cookies, capture keystrokes, redirect users to phishing sites, or perform actions on behalf of the victim user. Technical details and proof of concept are available at the GitHub PoC Repository.

Detection Methods for CVE-2026-3766

Indicators of Compromise

• Unusual or suspicious content in the fullname field of user profiles containing HTML tags or JavaScript code
• Web application logs showing profile update requests with encoded characters like <script>, onerror, onload, or other event handlers
• Reports from users experiencing unexpected browser behavior when viewing profile pages
• Session anomalies or unauthorized actions traced back to profile viewing activities

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block XSS payloads in POST requests to edit-profile.php
• Configure intrusion detection systems to alert on common XSS patterns in HTTP traffic targeting the pharmacy management application
• Review web server access logs for suspicious parameters containing script tags or JavaScript event handlers
• Deploy client-side Content Security Policy (CSP) violation reporting to detect script injection attempts

Monitoring Recommendations

• Enable detailed logging for all profile modification requests, capturing full parameter values for forensic analysis
• Monitor database fields storing user profile information for the presence of script tags or encoded malicious payloads
• Set up alerts for unusual patterns in user profile data that contain HTML metacharacters
• Regularly audit user-submitted content in the application database for stored XSS indicators

How to Mitigate CVE-2026-3766

Immediate Actions Required

• Restrict access to the Web-based Pharmacy Product Management System to trusted internal networks only
• Implement input validation on the server side to reject profile updates containing HTML or script content
• Apply output encoding to all user-supplied data before rendering it in HTML pages
• Consider disabling profile editing functionality until a proper fix is implemented

Patch Information

No official vendor patch has been released for this vulnerability at the time of publication. Organizations using SourceCodester Web-based Pharmacy Product Management System 1.0 should monitor the SourceCodester website for security updates. Additional vulnerability information is available through VulDB #349744.

Workarounds

• Implement server-side input validation using an allowlist approach, permitting only alphanumeric characters and common punctuation in the fullname field
• Apply HTML entity encoding to all user-supplied data before outputting it to web pages using functions like htmlspecialchars() in PHP
• Deploy a Web Application Firewall with XSS protection rules in front of the application
• Implement Content Security Policy (CSP) headers to mitigate the impact of successful XSS attacks by restricting script execution

# Example Apache configuration to add CSP headers
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'"
    Header set X-XSS-Protection "1; mode=block"
    Header set X-Content-Type-Options "nosniff"
</IfModule>