CVE-2026-13557: Hotel Management System XSS Vulnerability

CVE-2026-13557 Overview

CVE-2026-13557 is a cross-site scripting (XSS) vulnerability [CWE-79] in itsourcecode Online Hotel Management System 1.0. The flaw resides in the POST request handler at /admin/mod_room/controller.php?action=add, where the Name parameter is not properly sanitized before being reflected in the application response. An unauthenticated remote attacker can inject arbitrary JavaScript that executes in the browser of any user who interacts with the crafted content.

A public exploit for this issue is referenced in third-party vulnerability databases. Exploitation requires user interaction, and impact is limited to integrity of the affected page content.

Critical Impact
Attackers can execute arbitrary script in an administrator's browser session, enabling theft of session data, unauthorized actions inside the hotel management console, and phishing pivots against staff users.

Affected Products

itsourcecode Online Hotel Management System 1.0
Component: POST Request Handler at /admin/mod_room/controller.php
Affected parameter: Name (action=add)

Discovery Timeline

2026-06-29 - CVE-2026-13557 published to NVD
2026-06-29 - Last updated in NVD database

Technical Details for CVE-2026-13557

Vulnerability Analysis

The vulnerability is a reflected cross-site scripting flaw in the administrative room management module of the Online Hotel Management System. When an authenticated request is submitted to /admin/mod_room/controller.php?action=add, the application accepts the Name POST parameter and later renders that value back into an HTML response without contextual output encoding.

Because the parameter value is echoed into the HTML page as-is, an attacker can supply HTML or JavaScript payloads inside the Name field. Any such payload runs with the privileges of the browser session that loads the response. In an administrative panel, this typically means execution inside a privileged staff session.

The attack requires user interaction, since the victim must trigger the crafted request or visit an attacker-controlled page that submits it. However, the request can be delivered remotely without prior authentication of the attacker, and no additional privileges are required to craft the payload.

Root Cause

The root cause is missing input validation and missing output encoding for user-supplied data in the room add action handler. The application trusts the Name parameter and inserts it into the response body without escaping HTML metacharacters such as <, >, ", and '. This aligns with the classic pattern captured by CWE-79: Improper Neutralization of Input During Web Page Generation.

Attack Vector

The attack vector is network-based. An attacker crafts a malicious link or auto-submitting HTML form that targets /admin/mod_room/controller.php?action=add with a JavaScript payload embedded in the Name field. When an administrator or authenticated staff user is lured into triggering the request, the injected script executes inside their session context.

Typical exploitation outcomes include stealing session cookies, invoking authenticated administrative actions via forged in-page requests, and rewriting parts of the admin UI to harvest credentials. Additional technical detail is available in the GitHub CVE Issue Discussion and the VulDB CVE-2026-13557 entry.

Detection Methods for CVE-2026-13557

Indicators of Compromise

POST requests to /admin/mod_room/controller.php?action=add where the Name parameter contains HTML tags, <script> blocks, javascript: URIs, or event handlers such as onerror= and onload=.
Unexpected outbound requests from admin browsers to unfamiliar domains shortly after visiting the room management page.
Administrator session identifiers appearing in web server access logs referred from external sites.

Detection Strategies

Inspect HTTP access logs for POST bodies or query fragments containing encoded angle brackets (%3C, %3E) targeting the room controller endpoint.
Deploy a Web Application Firewall (WAF) rule that flags XSS signatures against /admin/mod_room/controller.php.
Correlate admin authentication events with anomalous JavaScript-triggered API calls originating from the same session.

Monitoring Recommendations

Enable verbose logging on the admin portal and forward logs to a centralized analytics platform for pattern matching.
Alert on admin sessions exhibiting DOM-triggered request bursts or navigation to external hosts immediately after form submission.
Track new or modified room records containing script-like content in the Name field as potential stored-payload attempts.

How to Mitigate CVE-2026-13557

Immediate Actions Required

Restrict access to /admin/mod_room/controller.php to trusted internal networks or VPN clients until a fix is deployed.
Require administrators to log out of unrelated browser sessions before using the hotel management console.
Deploy WAF rules that block requests where the Name parameter contains HTML tags or script keywords.

Patch Information

At time of publication, no official vendor patch has been referenced in the NVD entry for CVE-2026-13557. Operators of itsourcecode Online Hotel Management System 1.0 should monitor the IT Source Code Resource for updates and consult the VulDB Vulnerability #374565 advisory for further remediation guidance.

Workarounds

Apply server-side input validation on the Name parameter, rejecting characters outside an allow-list of alphanumerics and spaces.
Add contextual output encoding, such as HTML entity encoding, wherever the Name field is rendered in responses.
Enforce a strict Content Security Policy (CSP) that disallows inline scripts and restricts script sources to trusted origins.
Set the HttpOnly and SameSite=Strict attributes on administrative session cookies to reduce impact of successful XSS.

bash

# Example nginx WAF-style rule to block script payloads on the vulnerable endpoint
location /admin/mod_room/controller.php {
    if ($request_method = POST) {
        if ($request_body ~* "(<script|onerror=|onload=|javascript:)") {
            return 403;
        }
    }
}