CVE-2025-70890: Cyber Cafe Management System XSS Flaw

CVE-2025-70890 Overview

A stored cross-site scripting (XSS) vulnerability has been identified in Cyber Cafe Management System v1.0, a PHP-based application developed by PHP Gurukul. This vulnerability allows an authenticated attacker to inject arbitrary JavaScript code into the username parameter via the add-users.php endpoint. The malicious payload is persistently stored in the application's database and executed in victims' browsers whenever the affected page is accessed, creating a persistent attack vector that can impact multiple users over time.

Critical Impact

Authenticated attackers can achieve persistent JavaScript execution in victim browsers, potentially leading to session hijacking, credential theft, administrative account compromise, or further attacks against other users of the Cyber Cafe Management System.

Affected Products

• Phpgurukul Cyber Cafe Management System version 1.0
• Deployments using add-users.php endpoint for user management
• PHP/MySQL-based Cyber Cafe Management System installations

Discovery Timeline

• 2026-01-15 - CVE CVE-2025-70890 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2025-70890

Vulnerability Analysis

This stored XSS vulnerability (CWE-79) affects the user creation functionality within the Cyber Cafe Management System. The application fails to properly sanitize user-supplied input in the username parameter before storing it in the database and subsequently rendering it in web pages. When an administrator or other user views pages that display the stored username, the malicious JavaScript payload executes within their browser context.

The attack requires authentication to inject the payload, but the impact extends to any user who views the compromised data, including administrators with elevated privileges. This makes the vulnerability particularly dangerous in multi-user environments where administrative interfaces display user information.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the add-users.php endpoint. The application accepts user input for the username parameter without sanitizing special characters such as <, >, ", and '. When this unsanitized data is stored and later rendered in HTML contexts, the browser interprets injected script tags or event handlers as legitimate code rather than data.

Proper remediation requires implementing both input validation to restrict allowed characters in usernames and output encoding (HTML entity encoding) when rendering user-supplied data in HTML contexts.

Attack Vector

The attack is executed via the network against the add-users.php endpoint. An authenticated attacker submits a malicious username containing JavaScript code (e.g., <script> tags or event handlers like onmouseover). The payload is stored in the application's MySQL database. When any user, particularly an administrator, views a page displaying the stored username (such as user lists or profile pages), the injected JavaScript executes in their browser session.

This enables various attack scenarios including session cookie theft, keylogging, phishing overlays, defacement, or triggering actions on behalf of the victim. The persistent nature means the attack remains effective until the malicious data is manually removed from the database.

Detection Methods for CVE-2025-70890

Indicators of Compromise

• Unexpected JavaScript code or HTML tags present in username fields within the database
• Browser console errors or unexpected script executions when viewing user management pages
• Suspicious entries in web server access logs showing encoded script tags in POST parameters to add-users.php
• Reports of session hijacking or unauthorized administrative actions

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block XSS payloads in POST parameters
• Review database records in user tables for entries containing <script>, javascript:, or event handler attributes
• Deploy Content Security Policy (CSP) headers to restrict inline script execution and report violations
• Monitor application logs for unusual patterns in user creation requests

Monitoring Recommendations

• Enable detailed logging for all requests to add-users.php and other user management endpoints
• Configure alerts for CSP violation reports that may indicate XSS exploitation attempts
• Implement database integrity monitoring to detect suspicious content in user-related tables
• Review authentication and session logs for signs of session theft or unauthorized access following XSS execution

How to Mitigate CVE-2025-70890

Immediate Actions Required

• Audit existing user records in the database for malicious JavaScript content and remove any identified payloads
• Restrict access to the Cyber Cafe Management System to trusted networks until patches or mitigations are applied
• Implement Web Application Firewall rules to filter XSS payloads in request parameters
• Consider temporarily disabling user creation functionality if the system must remain accessible

Patch Information

No official vendor patch has been confirmed at this time. Organizations should monitor the PHP Gurukul project page for updates. A proof-of-concept and additional details are available in the GitHub CVE-2025-70890 repository.

Given the nature of PHP Gurukul projects, organizations may need to implement manual code fixes or consider alternative solutions if patches are not provided in a timely manner.

Workarounds

• Apply input validation to the username parameter in add-users.php to reject characters commonly used in XSS attacks (<, >, ", ', &)
• Implement output encoding using PHP functions like htmlspecialchars() or htmlentities() when displaying user-supplied data
• Deploy Content Security Policy headers with strict directives to prevent inline script execution
• Use HTTP-only and Secure flags on session cookies to limit the impact of successful XSS exploitation

# Apache configuration example - Add Content Security Policy header
# Add to .htaccess or Apache configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'none';"
Header set X-Content-Type-Options "nosniff"
Header set X-XSS-Protection "1; mode=block"