CVE-2026-3763: Simple Flight Ticket Booking System XSS Flaw

CVE-2026-3763 Overview

A Cross-Site Scripting (XSS) vulnerability has been identified in code-projects Simple Flight Ticket Booking System version 1.0. The vulnerability exists within the showhistory.php file, where improper input sanitization allows attackers to inject malicious scripts. This vulnerability can be exploited remotely without authentication, enabling attackers to execute arbitrary JavaScript code in the context of a victim's browser session.

Critical Impact

Remote attackers can exploit this XSS vulnerability to steal session cookies, perform phishing attacks, or redirect users to malicious websites through the vulnerable showhistory.php endpoint.

Affected Products

• Carmelo Simple Flight Ticket Booking System 1.0
• code-projects Simple Flight Ticket Booking System 1.0

Discovery Timeline

• March 8, 2026 - CVE-2026-3763 published to NVD
• March 9, 2026 - Last updated in NVD database

Technical Details for CVE-2026-3763

Vulnerability Analysis

This Cross-Site Scripting (XSS) vulnerability (CWE-79) resides in the showhistory.php file of the Simple Flight Ticket Booking System. The application fails to properly sanitize user-supplied input before rendering it in the browser, allowing malicious actors to inject arbitrary HTML or JavaScript code. When a victim views the affected page, the injected script executes within their browser context, potentially compromising their session or stealing sensitive information.

The vulnerability is network-accessible and requires user interaction—specifically, a victim must navigate to a page containing the malicious payload. The exploit has been publicly disclosed, which increases the risk of exploitation in the wild. For additional technical details, refer to the GitHub XSS Vulnerability Exploit repository.

Root Cause

The root cause of this vulnerability is improper input validation and output encoding within the showhistory.php file. User-controlled data is directly reflected in the HTML response without adequate sanitization, allowing script injection. This is a common flaw in web applications that fail to implement proper output encoding or Content Security Policy (CSP) headers.

Attack Vector

The attack vector is network-based, requiring an attacker to craft a malicious URL or inject payload data that gets processed by showhistory.php. When a victim accesses the crafted URL or views content containing the malicious payload, the injected JavaScript executes in their browser. This can lead to session hijacking, credential theft, or redirection to phishing pages.

The vulnerability mechanism involves injecting malicious script tags or event handlers into parameters processed by showhistory.php. When the server reflects this input without proper encoding, the browser interprets the injected content as legitimate script code and executes it within the security context of the vulnerable application. For detailed technical analysis, see the VulDB #349741 entry.

Detection Methods for CVE-2026-3763

Indicators of Compromise

• Suspicious HTTP requests to showhistory.php containing encoded script tags or JavaScript event handlers
• Browser console errors or unexpected script execution on pages displaying flight history
• Unusual outbound connections from user browsers to unknown external domains
• Log entries showing URL parameters with <script>, javascript:, or HTML event attributes like onerror, onload

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS payloads in requests to showhistory.php
• Monitor application logs for requests containing HTML special characters or encoded script content
• Deploy browser-based monitoring solutions to detect unauthorized script execution
• Use SentinelOne Singularity XDR to correlate web application logs with endpoint telemetry for comprehensive threat detection

Monitoring Recommendations

• Enable detailed logging for all requests to the showhistory.php endpoint
• Configure alerts for requests containing potential XSS patterns such as <script>, %3Cscript%3E, or JavaScript protocol handlers
• Monitor for anomalous session behavior that may indicate session hijacking following XSS exploitation

How to Mitigate CVE-2026-3763

Immediate Actions Required

• Restrict access to the showhistory.php file until a patch is available
• Implement Content Security Policy (CSP) headers to prevent inline script execution
• Deploy WAF rules to filter known XSS attack patterns targeting the affected endpoint
• Review and sanitize all user input before processing in the application

Patch Information

As of the last update on March 9, 2026, no official vendor patch has been released for this vulnerability. Organizations using the Simple Flight Ticket Booking System should monitor the Code Projects Resource Hub for security updates. Given the public disclosure of the exploit, implementing compensating controls is strongly recommended until an official patch becomes available.

Workarounds

• Implement server-side input validation to strip or encode HTML special characters in all user inputs
• Add HTTP response headers including Content-Security-Policy: default-src 'self' to prevent execution of inline scripts
• Use output encoding functions (e.g., htmlspecialchars() in PHP) when rendering user-supplied data
• Consider disabling the showhistory.php functionality if it is not critical to operations

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