CVE-2026-81273 in FluentBooking Pro Plugin
Summary
by MITRE • 08/27/2026
Unauthenticated Cross Site Request Forgery (CSRF) in FluentBooking Pro <= 2.2.4 versions.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified as an unauthenticated Cross-Site Request Forgery within FluentBooking Pro versions up to and including 2.2.4 represents a critical security flaw that undermines the integrity of administrative actions performed through the web application interface. This specific type of attack exploits the inherent trust that many web browsers place in websites, allowing an attacker to trick authenticated users into performing unintended actions without their knowledge or consent. In this context, because the vulnerability is unauthenticated, it implies that the malicious requests do not require prior login credentials from the victim at the time of exploitation, although they typically target sessions where administrative privileges are active. The core technical flaw lies in the application's failure to implement adequate anti-CSRF mechanisms, such as synchronizer tokens or custom header validation, for state-changing operations like creating bookings, modifying settings, or deleting data.
From a technical perspective, CSRF attacks rely on the fact that web applications often use session cookies to maintain user identity and do not verify whether a request originated from a legitimate source within the application itself. When FluentBooking Pro fails to validate these origins, an attacker can craft a malicious webpage containing hidden forms or JavaScript code designed to send HTTP requests to the vulnerable endpoints of the booking system. If a victim with administrative privileges visits this malicious page while logged into their WordPress dashboard, the browser will automatically attach any relevant session cookies associated with that domain. Consequently, the server processes these requests as if they were legitimate actions initiated by the administrator, leading to unauthorized modifications or deletions within the application's database and configuration settings.
The operational impact of this vulnerability is significant for organizations relying on FluentBooking Pro for managing appointments, services, or reservations. An attacker could exploit this flaw to create fraudulent bookings that consume resources, delete critical booking data causing business disruption, or alter system configurations to facilitate further attacks such as cross-site scripting or unauthorized access. The lack of authentication requirements for the CSRF payload means that social engineering tactics are highly effective; a simple link sent via email or instant message can trigger the attack if the victim is currently authenticated in their browser session. This compromises not only data integrity but also availability and confidentiality, potentially leading to financial loss and reputational damage depending on the scale of exploitation.
This vulnerability aligns with CWE-352, which describes Cross-Site Request Forgery as a weakness where an attacker causes a user to submit a request that they did not intend to submit. Furthermore, in terms of offensive security frameworks like MITRE ATT&CK, this activity falls under the Tactic Execution and potentially Tactic Persistence if used to maintain access or modify configurations for long-term control. The specific technique often maps to TA0005 Defense Evasion when attempting to bypass detection by mimicking legitimate user traffic, though it is primarily an exploitation of trust mechanisms rather than a direct evasion of security controls in the traditional sense.
To mitigate this vulnerability, immediate action should be taken by upgrading FluentBooking Pro to version 2.2.5 or later where these issues have been addressed with proper CSRF token implementation. For environments that cannot immediately upgrade, administrators can implement server-side mitigations such as enforcing strict origin and referrer header checks on sensitive endpoints. Additionally, enabling two-factor authentication for all administrative accounts adds a layer of defense by requiring secondary verification even if session cookies are hijacked or misused in this manner. Regular security audits and the use of Web Application Firewalls configured to detect anomalous request patterns can also help identify and block attempted CSRF exploits before they result in successful compromise.