CVE-2025-54729 is a Stored Cross-Site Scripting (XSS) vulnerability identified in the Webba Appointment Booking plugin, specifically affecting versions up to 6.0.5. This vulnerability arises due to improper neutralization of input during web page generation, classified under CWE-79. Stored XSS occurs when malicious scripts injected by an attacker are permanently stored on the target server, such as in a database, and then served to users when they access the affected pages. In this case, the Webba Booking plugin fails to adequately sanitize or encode user-supplied input before rendering it in web pages, allowing attackers with at least some level of authenticated access (as indicated by the CVSS vector requiring high privileges and user interaction) to inject malicious JavaScript code. When other users or administrators view the affected pages, the malicious script executes in their browsers, potentially leading to session hijacking, unauthorized actions, or data theft. The CVSS score of 5.9 (medium severity) reflects that exploitation requires network access, low attack complexity, high privileges, and user interaction, with partial impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that the vulnerability is newly disclosed and may require prompt attention from administrators using this plugin. The vulnerability affects a widely used WordPress booking plugin, which is often deployed by small to medium businesses for appointment scheduling on their websites.

For European organizations, the impact of this vulnerability can be significant, especially for businesses relying on Webba Booking for customer appointment management, such as healthcare providers, salons, legal services, and other client-facing sectors. Exploitation could lead to unauthorized access to user sessions, enabling attackers to impersonate legitimate users or administrators, manipulate booking data, or steal sensitive customer information. This can result in reputational damage, regulatory non-compliance (notably under GDPR due to potential personal data exposure), and operational disruptions. Since the vulnerability requires authenticated access and user interaction, insider threats or compromised accounts could be leveraged to exploit it. Additionally, the cross-site scripting nature may facilitate phishing or social engineering attacks targeting employees or customers. The partial impact on availability could disrupt booking services, affecting business continuity. Given the widespread use of WordPress in Europe and the popularity of appointment booking plugins, the vulnerability poses a tangible risk to a broad range of organizations.

Organizations should immediately audit their use of the Webba Booking plugin and verify the version in use. Until an official patch is released, administrators should consider the following specific mitigations: 1) Restrict plugin access to only trusted, necessary users with minimal privileges to reduce the risk of exploitation. 2) Implement Web Application Firewall (WAF) rules to detect and block typical XSS payloads targeting the plugin's input fields. 3) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers accessing the affected sites. 4) Conduct thorough input validation and output encoding on any custom integrations or extensions interacting with the plugin. 5) Monitor logs for unusual activity or injection attempts related to booking forms or plugin endpoints. 6) Educate users and administrators about the risks of phishing and social engineering that could facilitate exploitation. Once a patch is available, prioritize immediate update of the plugin to the fixed version. Additionally, review and harden authentication mechanisms to prevent account compromise that could enable exploitation.