CVE-2023-2416 in Online Booking & Scheduling Calendar Plugin
Summary
by MITRE • 06/03/2023
The Online Booking & Scheduling Calendar for WordPress by vcita plugin for WordPress is vulnerable to Cross-Site Request Forgery due to a missing nonce check on the vcita_logout_callback function in versions up to, and including, 4.5. This makes it possible for unauthenticated to logout a vctia connected account which would cause a denial of service on the appointment scheduler, via a forged request granted they can trick a site user into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 04/09/2026
The vulnerability identified in CVE-2023-2416 affects the Online Booking & Scheduling Calendar for WordPress plugin developed by vcita, specifically targeting versions up to and including 4.5. This represents a critical security flaw that undermines the integrity of user authentication processes within WordPress environments. The plugin's failure to implement proper nonce validation creates an exploitable condition that can be leveraged by malicious actors to disrupt legitimate user sessions and compromise the availability of appointment scheduling services. The vulnerability resides within the vcita_logout_callback function, which lacks the essential cryptographic token verification that would prevent unauthorized logout operations.
This cross-site request forgery vulnerability operates through a sophisticated attack vector that exploits the trust relationship between the WordPress site and authenticated users. The absence of nonce verification means that an attacker can craft malicious requests that appear to originate from legitimate administrative processes. When a victim user clicks on a malicious link or visits a compromised webpage, their session can be terminated without their knowledge or consent. The technical flaw directly violates fundamental web security principles and represents a CWE-352 vulnerability, which specifically addresses cross-site request forgery conditions in web applications. The attack mechanism aligns with ATT&CK technique T1566.002, which describes the use of spearphishing attachments to gain initial access and execute malicious operations.
The operational impact of this vulnerability extends beyond simple session termination, creating a potential denial of service condition that severely disrupts business operations for organizations relying on appointment scheduling. When legitimate users are unexpectedly logged out, they lose access to their scheduled appointments and booking capabilities, effectively rendering the appointment system unusable for those affected individuals. The service disruption can cascade through business operations, particularly impacting organizations that depend heavily on automated scheduling systems for customer service delivery. This vulnerability particularly affects small to medium businesses that may not have robust security monitoring in place to detect such unauthorized session manipulation attempts, making them more susceptible to operational disruption and potential customer service degradation.
Mitigation strategies for this vulnerability require immediate implementation of security patches provided by the plugin vendor, as the issue stems from a fundamental lack of authentication verification in the logout callback mechanism. Organizations should implement comprehensive security monitoring to detect unauthorized logout attempts and establish network-level controls to prevent exploitation. The remediation process involves ensuring that all user-initiated actions, particularly those involving session management, require proper nonce validation before execution. Security teams should also consider implementing web application firewalls with CSRF protection capabilities and conduct thorough security assessments of all WordPress plugins to identify similar vulnerabilities. The fix should align with security best practices outlined in the OWASP Top Ten and should be validated through security testing to ensure that the nonce verification properly protects against unauthorized logout operations while maintaining legitimate user functionality.