CVE-2026-3983: Campcodes Athletic Meet System XSS Flaw

CVE-2026-3983 Overview

A Cross-Site Scripting (XSS) vulnerability has been discovered in Campcodes Division Regional Athletic Meet Game Result Matrix System version 2.1. This vulnerability affects the save-games.php file, where improper handling of the game_name argument allows attackers to inject malicious scripts. The attack can be performed remotely by authenticated users, and exploit code has been publicly released, increasing the risk of active exploitation.

Critical Impact

Remote attackers with low privileges can inject malicious scripts through the game_name parameter, potentially leading to session hijacking, data theft, or unauthorized actions on behalf of authenticated users.

Affected Products

• Campcodes Division Regional Athletic Meet Game Result Matrix System 2.1
• save-games.php component

Discovery Timeline

• 2026-03-12 - CVE-2026-3983 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2026-3983

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 save-games.php file within the application, where user-supplied input through the game_name parameter is not properly sanitized before being rendered in the web interface.

When a user submits data through the vulnerable endpoint, the application fails to encode or filter special characters that have significance in HTML/JavaScript contexts. This allows an attacker to craft a malicious payload that, when processed by the application, executes arbitrary JavaScript code in the victim's browser session.

The vulnerability requires the attacker to have low-level privileges (authenticated access) and some user interaction to trigger the payload execution. While the direct impact is limited to integrity modification without affecting confidentiality or availability of the vulnerable system, successful exploitation could lead to session token theft, credential harvesting through fake login forms, or performing actions on behalf of the victim user.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and output encoding in the save-games.php script. The game_name parameter accepts user input without proper sanitization, allowing HTML and JavaScript code to be stored and subsequently rendered in the browser without escaping. This is a classic stored XSS pattern where malicious content persists in the application's database and affects any user who views the tainted data.

Attack Vector

The attack is network-based, allowing remote exploitation by authenticated users. An attacker would craft a malicious game_name value containing JavaScript code and submit it through the application's game-saving functionality. When other users access pages displaying this game name, the injected script executes within their browser context, potentially compromising their session or performing unauthorized actions.

The vulnerability mechanism involves the following flow: user input is submitted via the game_name parameter to save-games.php, stored without sanitization, and later rendered in web pages without proper output encoding. Technical details and proof-of-concept information are available in the GitHub CVE Issue Discussion.

Detection Methods for CVE-2026-3983

Indicators of Compromise

• Unusual JavaScript patterns in game_name database fields containing <script>, onerror=, onload=, or similar event handlers
• HTTP requests to save-games.php containing encoded or obfuscated script payloads in the game_name parameter
• Unexpected outbound connections from user browsers to unfamiliar domains after viewing game results
• User reports of unexpected behavior or pop-ups when accessing the Game Result Matrix System

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block XSS payloads in POST parameters targeting save-games.php
• Deploy database monitoring to alert on insertion of HTML/JavaScript tags in the game_name column
• Configure intrusion detection systems to identify known XSS attack patterns in HTTP traffic
• Review application logs for unusual patterns in the game_name parameter submissions

Monitoring Recommendations

• Enable detailed logging for all requests to save-games.php including full parameter values
• Set up alerts for any input containing common XSS indicators such as angle brackets, script tags, or JavaScript event handlers
• Monitor for anomalous user behavior following access to game result pages
• Implement Content Security Policy (CSP) headers and monitor violation reports

How to Mitigate CVE-2026-3983

Immediate Actions Required

• Restrict access to save-games.php to only trusted administrators until a patch is available
• Implement server-side input validation to strip or reject HTML/JavaScript content from the game_name parameter
• Apply output encoding (HTML entity encoding) when displaying game_name values in web pages
• Review and sanitize existing database entries for potentially malicious content

Patch Information

No official vendor patch has been released at the time of this publication. Organizations using this software should monitor the vendor's website for security updates. Additional technical details are available through VulDB #350419 and the VulDB Submission #769720.

Workarounds

• Implement a Web Application Firewall with XSS filtering rules for the affected endpoint
• Add server-side input validation using a whitelist approach for the game_name parameter, allowing only alphanumeric characters and limited punctuation
• Apply HTML entity encoding to all user-supplied data before rendering in web pages
• Deploy Content Security Policy headers to prevent inline script execution and restrict script sources

# Example Apache mod_security rule to block XSS in game_name parameter
SecRule ARGS:game_name "@rx (?i)<script|javascript:|on\w+\s*=" \
    "id:100001,phase:2,deny,status:403,msg:'XSS attempt in game_name parameter'"