CVE-2026-13567: Online Music Site 1.0 XSS Vulnerability

CVE-2026-13567 Overview

CVE-2026-13567 is a cross-site scripting (XSS) vulnerability affecting code-projects Online Music Site 1.0. The flaw resides in the /Frontend/Feedback.php component's POST request handler. Attackers can inject malicious script content through the fname, femail, faddress, or fmessage parameters. The vulnerability is remotely exploitable and does not require authentication, though it does require user interaction to trigger the injected payload. Public exploit details have been released, increasing the likelihood of opportunistic exploitation against exposed deployments. The issue is classified under [CWE-79] (Improper Neutralization of Input During Web Page Generation).

Critical Impact
Attackers can execute arbitrary JavaScript in the browser context of users interacting with the feedback page, enabling session theft, phishing, and client-side data exfiltration.

Affected Products

code-projects Online Music Site 1.0
/Frontend/Feedback.php POST request handler
Deployments exposing the feedback form to untrusted users

Discovery Timeline

2026-06-29 - CVE-2026-13567 published to NVD
2026-06-29 - Last updated in NVD database

Technical Details for CVE-2026-13567

Vulnerability Analysis

The vulnerability is a stored or reflected cross-site scripting flaw in the feedback submission workflow of code-projects Online Music Site 1.0. The /Frontend/Feedback.php endpoint accepts POST parameters fname, femail, faddress, and fmessage without applying output encoding or input sanitization. When these values are rendered back into HTML, the browser interprets attacker-controlled markup as executable script. An unauthenticated remote attacker submits a crafted payload, and any user who subsequently views the affected page executes the injected JavaScript. This class of flaw enables cookie theft, credential harvesting through injected forms, unauthorized actions on behalf of the victim, and drive-by redirection to attacker infrastructure.

Root Cause

The root cause is missing input validation and missing output encoding in the feedback handler. The application concatenates user-supplied POST values into HTML responses without applying context-appropriate escaping such as htmlspecialchars() in PHP. No allowlist filtering is applied to the four affected parameters. This is a textbook [CWE-79] pattern documented in the GitHub CVE Issue Tracker.

Attack Vector

Exploitation occurs over the network against the public-facing feedback form. The attacker submits a POST request containing a JavaScript payload in one of the vulnerable fields. Because the exploit has been published, attackers can weaponize the payload for phishing campaigns or automated scanners. Additional technical details are available at the VulDB Vulnerability Details page and the VulDB CTI Analysis. No verified proof-of-concept code is reproduced here; refer to the GitHub CVE Issue Tracker for the public write-up.

Detection Methods for CVE-2026-13567

Indicators of Compromise

POST requests to /Frontend/Feedback.php containing <script>, javascript:, onerror=, or onload= substrings in fname, femail, faddress, or fmessage parameters.
Unexpected outbound requests from user browsers to unknown domains after visiting the feedback page.
Feedback records in the database containing HTML tags or encoded script fragments.

Detection Strategies

Deploy a web application firewall (WAF) rule that inspects POST bodies to /Frontend/Feedback.php for XSS signatures.
Review application access logs for anomalous feedback submissions containing angle brackets, event handlers, or URL-encoded script markers.
Perform static analysis on the PHP source to confirm that all four parameters flow into HTML sinks without encoding.

Monitoring Recommendations

Monitor web server logs for repeated POSTs to the feedback endpoint from single source IPs.
Alert on Content Security Policy (CSP) violation reports originating from feedback-related pages.
Track browser-side JavaScript errors that may indicate injected payload execution attempts.

How to Mitigate CVE-2026-13567

Immediate Actions Required

Restrict or disable public access to /Frontend/Feedback.php until a fix is deployed.
Deploy WAF signatures blocking XSS payloads targeting the four affected POST parameters.
Purge any stored feedback records containing HTML or script markup from the database.
Rotate session cookies for users who may have interacted with the feedback page since deployment.

Patch Information

No official vendor patch is referenced in the enriched data at the time of publication. Consult the Code Projects Resource Hub and the VulDB CVE Reference for updates. Administrators should apply source-level fixes by wrapping all output of the four parameters in htmlspecialchars($value, ENT_QUOTES, 'UTF-8') and validating input against an allowlist.

Workarounds

Apply server-side input validation rejecting angle brackets and event-handler patterns in feedback fields.
Enable a strict Content Security Policy that disallows inline scripts and untrusted script sources.
Set the HttpOnly and Secure flags on session cookies to reduce impact of successful script injection.
Place the application behind a reverse proxy that enforces request body inspection.

bash

# Configuration example: minimal CSP header for Apache to reduce XSS impact
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'none'"
Header set X-Content-Type-Options "nosniff"
Header set X-Frame-Options "DENY"