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

CVE-2026-3763 Overview

CVE-2026-3763 is a cross-site scripting (XSS) vulnerability [CWE-79] in code-projects Simple Flight Ticket Booking System 1.0. The flaw resides in an unspecified function within the showhistory.php file. Attackers can manipulate input handled by this script to inject client-side code into responses rendered to other users. The vulnerability is exploitable remotely over the network and requires user interaction to trigger the injected payload. A public proof-of-concept exploit exists, increasing the likelihood of opportunistic abuse against deployed instances.

Critical Impact
Successful exploitation enables attackers to execute arbitrary JavaScript in a victim's browser session, leading to session hijacking, credential theft, or unauthorized actions within the booking application.

Affected Products

Carmelo Simple Flight Ticket Booking System 1.0
Vulnerable component: showhistory.php
CPE: cpe:2.3:a:carmelo:simple_flight_ticket_booking_system:1.0:*:*:*:*:*:*:*

Discovery Timeline

2026-03-08 - CVE-2026-3763 published to NVD
2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-3763

Vulnerability Analysis

The vulnerability is a reflected or stored cross-site scripting issue affecting the showhistory.php endpoint of the Simple Flight Ticket Booking System. The application fails to properly sanitize or encode user-controllable input before embedding it within HTML output. As a result, attacker-supplied JavaScript executes in the context of any user who visits a crafted URL or views attacker-controlled history data.

Because the application handles booking history, the injected script can read session cookies, modify rendered booking details, or perform unauthorized requests on behalf of the authenticated user. Exploitation requires user interaction, typically clicking a malicious link or visiting a page containing the payload.

Root Cause

The root cause is missing output encoding and inadequate input validation in showhistory.php. User-supplied parameters are reflected into the HTML response without contextual escaping, allowing <script> tags or event-handler attributes to be interpreted by the browser. This pattern is classified as Improper Neutralization of Input During Web Page Generation [CWE-79].

Attack Vector

An attacker crafts a URL or input payload containing JavaScript and delivers it to a victim, often through phishing or a malicious link. When the victim accesses showhistory.php with the crafted parameter, the injected script executes in the victim's browser under the application's origin. The exploit is publicly documented in the GitHub XSS Vulnerability PoC, which provides reproduction steps.

No synthetic exploitation code is reproduced here. Refer to the VulDB entry #349741 for additional technical context.

Detection Methods for CVE-2026-3763

Indicators of Compromise

HTTP requests to showhistory.php containing URL-encoded <script>, onerror=, onload=, or javascript: tokens in query parameters.
Web server logs showing repeated probes against showhistory.php from a single source with anomalous payloads.
Unexpected outbound requests from user browsers to attacker-controlled domains after visiting the application.

Detection Strategies

Inspect web server and application logs for parameter values containing HTML or JavaScript syntax targeting showhistory.php.
Deploy a Web Application Firewall (WAF) rule set tuned for OWASP XSS signatures across all PHP endpoints.
Use dynamic application security testing (DAST) tools to fuzz parameters and confirm reflected output behavior.

Monitoring Recommendations

Enable verbose access logging on the PHP application and forward logs to a centralized analytics platform.
Alert on anomalous user-agent strings or referrers correlated with requests to showhistory.php.
Monitor browser Content Security Policy (CSP) violation reports to identify in-the-wild injection attempts.

How to Mitigate CVE-2026-3763

Immediate Actions Required

Restrict public access to the Simple Flight Ticket Booking System until a vendor fix or hot patch is applied.
Apply input validation and output encoding to all parameters processed by showhistory.php.
Deploy a Content Security Policy that disallows inline scripts and unauthorized script sources.

Patch Information

No official vendor patch has been published at the time of writing. The vendor advisory references available are limited to VulDB CTI #349741 and the Code Projects site. Administrators should monitor the vendor channel for updated releases and apply compensating controls in the interim.

Workarounds

Place the application behind a WAF with strict XSS filtering rules for query and POST parameters.
Apply server-side sanitization by passing all reflected values through htmlspecialchars($value, ENT_QUOTES, 'UTF-8') before output.
Set HttpOnly and Secure flags on session cookies to limit script-based session theft.
Implement a restrictive CSP header such as Content-Security-Policy: default-src 'self'; script-src 'self'.

bash

# Example Apache configuration to add security headers
Header always set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'"
Header always set X-XSS-Protection "1; mode=block"
Header always set X-Content-Type-Options "nosniff"
Header edit Set-Cookie ^(.*)$ $1;HttpOnly;Secure;SameSite=Strict