The vulnerability identified as CVE-2025-66918 affects edoc-doctor-appointment-system version 1.0.1, a healthcare appointment management application. The issue is a Cross Site Scripting (XSS) flaw located in the admin/add-session.php script, specifically through the 'title' parameter. XSS vulnerabilities occur when an application does not properly sanitize user-supplied input, allowing attackers to inject malicious scripts that execute in the browsers of users who view the affected page. In this case, an attacker can craft a malicious payload in the 'title' parameter that, when processed by the administrative interface, executes arbitrary JavaScript code. This can lead to session hijacking, credential theft, or unauthorized actions performed with the privileges of the administrator. The vulnerability requires the attacker to have access to the administrative interface or to trick an administrator into visiting a maliciously crafted URL or inputting malicious data. There is no CVSS score assigned yet, and no known exploits have been reported in the wild. The lack of patch links suggests that a fix may not yet be publicly available. The vulnerability impacts the confidentiality and integrity of the system by potentially exposing sensitive administrative functions and data to attackers. The affected version is 1.0.1, but no other versions are specified. The vulnerability was published on December 11, 2025, with the reservation date on December 8, 2025.

For European organizations, particularly those in the healthcare sector using edoc-doctor-appointment-system, this XSS vulnerability could lead to unauthorized administrative access or manipulation of appointment data. Attackers exploiting this flaw could hijack administrator sessions, steal credentials, or perform unauthorized administrative actions, potentially disrupting healthcare services or exposing sensitive patient information. The impact on confidentiality is significant as attackers could access protected health information. Integrity is also at risk since attackers could modify appointment schedules or administrative settings. Availability impact is limited but possible if attackers disrupt administrative functions. Given the administrative nature of the vulnerability, exploitation requires access to the admin interface, limiting the attack surface but increasing the risk if credentials are compromised or if phishing is successful. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as healthcare systems are high-value targets in Europe.

To mitigate this vulnerability, organizations should implement strict input validation and output encoding on the 'title' parameter within the admin/add-session.php script to prevent malicious script injection. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in the administrative interface. Limit administrative access through network segmentation, VPNs, or IP whitelisting to reduce exposure. Enforce strong authentication mechanisms, including multi-factor authentication (MFA), for all administrative users. Monitor logs for unusual activity related to the admin interface and conduct regular security audits of the application. Since no patch is currently available, consider temporarily disabling or restricting access to the vulnerable functionality if feasible. Stay updated with vendor advisories for patches or updates addressing this vulnerability and apply them promptly once released. Educate administrators on phishing risks to prevent social engineering attacks that could facilitate exploitation.