CVE-2025-66530 is a missing authorization vulnerability identified in the Webba Appointment Booking plugin (Webba Booking) for WordPress, affecting versions up to and including 6.2.1. The vulnerability stems from incorrectly configured access control security levels, which fail to properly restrict user privileges. This misconfiguration allows attackers with limited privileges (PR:L) to perform unauthorized actions remotely (AV:N) without requiring any user interaction (UI:N). The vulnerability impacts the confidentiality, integrity, and availability of the affected systems, as attackers can potentially access sensitive booking data, modify appointments, or disrupt service availability. The CVSS 3.1 base score of 8.8 indicates a high severity, with low attack complexity (AC:L) and no scope change (S:U). Although no known exploits are currently reported in the wild, the nature of the vulnerability makes it a prime target for attackers seeking to compromise appointment booking systems, which are critical for many businesses. The vulnerability was published on December 9, 2025, and is tracked under CVE-2025-66530. The lack of available patches at the time of publication necessitates immediate attention to access control configurations and monitoring for updates from the vendor. This vulnerability is particularly concerning for organizations relying on Webba Booking for managing client appointments, as unauthorized access could lead to data breaches, service disruptions, and reputational damage.

For European organizations, the impact of CVE-2025-66530 can be significant, especially for businesses in healthcare, legal, education, and service industries that rely heavily on appointment booking systems. Unauthorized access could lead to exposure of sensitive personal data, including client names, contact details, and appointment information, violating GDPR and other privacy regulations. Integrity of booking data could be compromised, allowing attackers to alter or delete appointments, causing operational disruptions and loss of trust. Availability may also be affected if attackers exploit the vulnerability to disrupt the booking service, leading to business interruptions and potential financial losses. Given the high CVSS score and the nature of the vulnerability, organizations face risks of targeted attacks aiming to exploit weak access controls. The absence of known exploits in the wild currently provides a window for proactive mitigation, but the threat landscape could evolve rapidly. Compliance risks and potential regulatory penalties add to the impact severity for European entities.

1. Immediately audit and review access control configurations within the Webba Booking plugin to ensure that only authorized users have appropriate permissions. 2. Restrict user roles and privileges to the minimum necessary, avoiding granting elevated permissions to untrusted users. 3. Monitor official vendor channels and security advisories for patches or updates addressing CVE-2025-66530 and apply them promptly once available. 4. Implement web application firewalls (WAF) with custom rules to detect and block suspicious requests targeting the booking system. 5. Conduct regular security assessments and penetration testing focused on access control mechanisms within the booking platform. 6. Enable detailed logging and monitoring of booking system activities to detect unauthorized access attempts early. 7. Educate administrative users on the importance of secure configuration and the risks of privilege escalation. 8. Consider isolating the booking system within segmented network zones to limit potential lateral movement in case of compromise. 9. Backup booking data regularly and verify restoration processes to minimize impact from potential data tampering or deletion. 10. Review and update incident response plans to include scenarios involving booking system compromise.