CVE-2023-51315 identifies multiple stored Cross-Site Scripting (XSS) vulnerabilities in PHPJabbers Restaurant Booking System version 3.0. The affected parameters include seat_name, plugin_sms_api_key, plugin_sms_country_code, title, and name, which do not properly sanitize or encode user-supplied input before storing and rendering it in the application interface. Stored XSS occurs when malicious scripts injected by an attacker are saved on the server and subsequently executed in the browsers of users who view the affected pages. This vulnerability requires an attacker to have low-level authenticated access to inject payloads, and victim users must interact with the compromised content for exploitation to succeed. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) indicates network attack vector, low attack complexity, requiring privileges and user interaction, with scope changed due to potential impact beyond the vulnerable component. The impact primarily affects confidentiality and integrity by enabling theft of session tokens, user impersonation, or unauthorized actions within the booking system. No availability impact is noted. No known exploits have been reported in the wild, and no official patches are currently available, increasing the urgency for organizations to implement mitigations. The vulnerability is classified under CWE-79, a common web application security weakness. Given the nature of the booking system, exploitation could lead to unauthorized access to booking data or manipulation of reservations, affecting business operations and customer trust.

For European organizations, particularly those in the hospitality and restaurant sectors using PHPJabbers Restaurant Booking System, this vulnerability poses a risk of unauthorized access and manipulation of booking data. Attackers exploiting stored XSS can hijack user sessions, deface web interfaces, or execute malicious actions under the guise of legitimate users, potentially leading to data breaches or reputational damage. Confidential customer information and business-critical booking details could be exposed or altered, undermining trust and compliance with data protection regulations such as GDPR. Although the vulnerability requires authenticated access and user interaction, the widespread use of web-based booking systems in Europe increases the attack surface. The absence of patches means organizations must rely on compensating controls to reduce risk. The impact on availability is minimal, but the integrity and confidentiality concerns could disrupt business continuity and customer relations if exploited.

Organizations should immediately implement strict input validation and output encoding for all user-supplied data in the affected parameters to prevent script injection. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. Limit user privileges to the minimum necessary, especially for accounts that can modify booking parameters. Monitor logs and user activities for unusual behavior indicative of XSS exploitation attempts. If possible, isolate the booking system within a segmented network zone to reduce lateral movement risks. Regularly back up booking data to enable recovery in case of compromise. Engage with PHPJabbers support or community forums to track patch releases or official advisories. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block XSS payloads targeting the vulnerable parameters. Educate staff about the risks of phishing or social engineering that could facilitate exploitation through user interaction.