CVE-2026-19057: Gastromenum Ticket System XSS Vulnerability

CVE-2026-19057 Overview

CVE-2026-19057 is a stored cross-site scripting (XSS) vulnerability in the Gastromenum Ticket and QR Menu System. The flaw stems from improper neutralization of user input during web page generation [CWE-79]. Authenticated attackers can inject malicious scripts that execute in the browsers of other users who view the affected pages. Because the scope is changed, injected payloads can affect users beyond the initial security boundary, including administrators or restaurant staff interacting with the QR menu and ticketing interfaces. The vulnerability affects all versions of Gastromenum Ticket and QR Menu System prior to 2026.08.31.

Critical Impact
Authenticated attackers can persist malicious JavaScript that executes in victim browsers, enabling session theft, credential harvesting, and unauthorized actions within the ticketing and menu management interfaces.

Affected Products

Gastromenum Ticket and QR Menu System versions before 2026.08.31
Web-facing ticketing components that render user-supplied input
QR menu management interfaces accessible to authenticated users

Discovery Timeline

2026-09-04 - CVE-2026-19057 published to NVD
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-19057

Vulnerability Analysis

The vulnerability is a stored XSS flaw classified under [CWE-79]. User-supplied content is accepted, persisted in application storage, and later reflected into rendered HTML without adequate encoding or sanitization. When another user loads the affected page, the browser parses the attacker-controlled payload as executable script.

Exploitation requires low-privilege authentication and user interaction to trigger the payload. The changed scope indicates the injected script can operate outside the vulnerable component's security boundary, expanding the potential victim population to administrators and other privileged operators of the platform.

Successful exploitation can lead to session hijacking, forced browser actions on behalf of victims, defacement of menu content, and phishing against restaurant operators who manage the system.

Root Cause

The application fails to apply output encoding or input sanitization to fields that store menu, ticket, or profile data. Persisted payloads are inserted directly into HTML contexts during page generation, allowing <script> tags and event handler attributes to execute as active content.

Attack Vector

An authenticated attacker submits a crafted payload through an input field exposed by the Gastromenum web application. The malicious content is stored server-side. When any user, including higher-privileged administrators, later views the page rendering that data, their browser executes the attacker's script under the origin of the vulnerable application.

The vulnerability mechanism involves persistent storage of unsanitized input followed by unsafe rendering in HTML output. See the Siber Güvenlik Advisory TR-26-1012 for further technical context.

Detection Methods for CVE-2026-19057

Indicators of Compromise

Stored records in menu, ticket, or profile fields containing HTML tags such as <script>, <img onerror=>, or <svg onload=>
Outbound requests from user browsers to unknown external domains following page loads
Unexpected administrative actions performed from legitimate authenticated sessions
Application logs showing input submissions containing encoded JavaScript payloads or javascript: URIs

Detection Strategies

Review database contents for stored HTML or JavaScript patterns in text fields intended for plain content
Deploy web application firewall (WAF) rules that inspect POST parameters for XSS payload signatures
Enable a strict Content Security Policy (CSP) and monitor report-uri endpoints for violations indicating injected scripts
Correlate authentication logs with unusual client-side behavior to identify session compromise

Monitoring Recommendations

Monitor administrative account activity for anomalous requests originating from legitimate sessions
Alert on repeated CSP violation reports referencing inline scripts or unexpected external origins
Track HTTP referrers and user-agent patterns for automated payload submission attempts

How to Mitigate CVE-2026-19057

Immediate Actions Required

Upgrade Gastromenum Ticket and QR Menu System to version 2026.08.31 or later
Audit stored content in menu, ticket, and profile fields for existing injected payloads and remove them
Force password resets and terminate active sessions for administrator accounts that may have viewed malicious content
Restrict access to the administrative interface using network-level controls until patching completes

Patch Information

The vendor addressed CVE-2026-19057 in Gastromenum Ticket and QR Menu System release 2026.08.31. Operators should apply the update immediately and verify installed versions across all instances. Refer to the Siber Güvenlik Advisory TR-26-1012 for vendor guidance.

Workarounds

Enforce a strict Content Security Policy that disables inline scripts and restricts external script sources
Deploy WAF rules to block common XSS payload patterns in POST requests to affected endpoints
Limit authenticated access to trusted operators and require multi-factor authentication for administrative logins

bash

# Example Content Security Policy header to mitigate stored XSS execution
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'none'; report-uri /csp-report";