CVE-2025-66530 identifies a missing authorization vulnerability in the Webba Appointment Booking plugin (Webba Booking) for WordPress, affecting versions up to and including 6.2.1. The vulnerability stems from improperly configured access control security levels, which means that certain functions or data that should be restricted to authorized users can be accessed or manipulated by unauthorized actors. This type of flaw typically allows attackers to bypass authentication or authorization checks, potentially enabling them to view, modify, or delete appointment bookings, access administrative features, or interfere with the booking system's normal operation. Although no public exploits have been reported, the vulnerability's nature suggests it could be exploited remotely without user interaction, depending on the plugin's deployment context. The absence of a CVSS score indicates that the vulnerability is newly published and not yet fully assessed. The Webba Booking plugin is widely used by businesses and organizations to manage appointments online, making this vulnerability relevant to many sectors, including healthcare, education, and professional services. The flaw could lead to unauthorized disclosure of sensitive client information, manipulation of booking schedules, and potential denial of service if attackers disrupt booking functionality. The vulnerability was reserved and published in early December 2025, with no patches currently linked, emphasizing the need for immediate attention from users of the affected versions.

For European organizations, the impact of CVE-2025-66530 could be significant, especially for those relying on Webba Booking for critical appointment scheduling. Unauthorized access could lead to exposure of personal data protected under GDPR, resulting in legal and financial repercussions. Integrity of booking data could be compromised, causing operational disruptions and loss of customer trust. Availability might also be affected if attackers manipulate or delete bookings, potentially leading to service outages or reputational damage. Sectors such as healthcare, legal, and financial services, which often handle sensitive client appointments, are particularly vulnerable. The impact extends beyond data loss to include compliance violations and potential fines. Additionally, attackers could leverage this vulnerability as a foothold for further network intrusion if the booking system is integrated with broader IT infrastructure. The lack of known exploits provides a window for mitigation, but organizations should act proactively to prevent exploitation.

Organizations should immediately inventory their use of the Webba Booking plugin and identify affected versions (up to 6.2.1). Although no official patches are currently linked, users should monitor the vendor’s website and trusted security advisories for updates and apply patches promptly once available. In the interim, review and tighten access control configurations within the plugin settings to ensure that sensitive functions are restricted to authorized users only. Implement web application firewalls (WAFs) with rules designed to detect and block unauthorized access attempts targeting the booking system. Conduct regular audits of booking data and logs to detect anomalies indicative of exploitation attempts. Limit exposure by restricting administrative access to trusted IP addresses and enforce strong authentication mechanisms for users with elevated privileges. Educate staff about the risks and signs of exploitation. Consider isolating the booking system from other critical infrastructure to contain potential breaches. Finally, ensure that backups of booking data are performed regularly and tested for integrity to enable recovery in case of data manipulation or loss.