CVE-2025-64381 is a Stored Cross-site Scripting (XSS) vulnerability identified in the wpdevelop Booking Calendar plugin for WordPress, affecting all versions up to 10.14.7. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows attackers to inject malicious JavaScript code that is stored persistently on the server. When other users access the affected pages, the malicious script executes in their browsers within the security context of the vulnerable site. This can lead to a range of malicious outcomes including session hijacking, theft of sensitive information such as cookies or credentials, defacement, or performing unauthorized actions on behalf of the user. The vulnerability does not require authentication to exploit, increasing its risk profile. No public exploits have been reported yet, but the nature of Stored XSS makes it a critical concern for websites handling user interactions and sensitive data. The Booking Calendar plugin is widely used for managing appointments and bookings, making it a valuable target for attackers aiming to compromise business operations or customer trust. The lack of a CVSS score indicates that the vulnerability is newly disclosed, but the technical details and typical impact of Stored XSS vulnerabilities justify a high severity rating. Organizations using this plugin should monitor for vendor patches and apply them promptly to mitigate risk.

For European organizations, this vulnerability poses significant risks to the confidentiality and integrity of user data and business operations. Exploitation could lead to unauthorized access to user sessions, enabling attackers to impersonate legitimate users, steal sensitive booking or customer information, and potentially escalate attacks within the network. This is particularly critical for businesses in sectors such as hospitality, healthcare, and professional services that rely on booking systems to manage client appointments. The Stored XSS can also damage organizational reputation and customer trust if exploited to deliver phishing or malware payloads. Additionally, regulatory implications under GDPR may arise if personal data is compromised, leading to potential fines and legal consequences. The ease of exploitation without authentication increases the likelihood of attacks, especially targeting high-traffic websites. The impact extends beyond individual businesses to their customers and partners, potentially causing cascading effects in the supply chain or service delivery.

1. Monitor wpdevelop official channels for security patches addressing CVE-2025-64381 and apply updates immediately once available. 2. Until patches are released, implement Web Application Firewalls (WAFs) with custom rules to detect and block typical XSS payloads targeting the Booking Calendar plugin. 3. Conduct thorough input validation and output encoding on all user-supplied data related to booking entries, ensuring special characters are properly sanitized before rendering. 4. Review and harden Content Security Policy (CSP) headers to restrict execution of unauthorized scripts on affected web pages. 5. Educate website administrators and developers on secure coding practices to prevent similar vulnerabilities in customizations or integrations. 6. Regularly audit and monitor logs for suspicious activities indicative of XSS exploitation attempts. 7. Consider isolating or limiting the Booking Calendar plugin’s access scope and permissions within the WordPress environment to reduce potential damage from exploitation.