The vulnerability CVE-2026-13567 in code-projects Online Music Site 1.0 arises from insufficient input sanitization in the POST request handler of /Frontend/Feedback.php. Manipulating the parameters fname, femail, faddress, or fmessage can lead to cross-site scripting, enabling attackers to execute arbitrary scripts in the context of the victim's browser. The attack can be performed remotely without authentication. Public exploit code is available, increasing the risk of exploitation. No official patch or remediation guidance has been provided by the vendor as of the published date.

Successful exploitation of this vulnerability can lead to the execution of arbitrary scripts in users' browsers, potentially resulting in session hijacking, defacement, or redirection to malicious sites. Since the vulnerability is in a feedback form, it may be triggered by unsuspecting users visiting crafted URLs or submitting malicious input. The CVSS score of 5.3 reflects a medium severity impact with low attack complexity and no privileges required.

No official patch or remediation is currently available for this vulnerability. Users and administrators should monitor the vendor's advisory channels for updates. As a temporary mitigation, input validation and output encoding should be implemented on the affected parameters (fname, femail, faddress, fmessage) to prevent script injection. Additionally, consider disabling or restricting access to the feedback functionality until a fix is released.