CVE-2024-0238 is a vulnerability identified in the EventON Premium WordPress plugin versions prior to 4.5.6 and the EventON WordPress plugin versions prior to 2.2.8. The core issue is a missing authorization check in an AJAX action handler. Specifically, the plugin fails to verify that the user initiating the AJAX request is authorized to update the post metadata associated with the plugin. This lack of authorization allows unauthenticated users—attackers without any login credentials—to update arbitrary post metadata. The vulnerability is classified under CWE-862 (Missing Authorization) and is also related to CWE-79 (Cross-Site Scripting), indicating that the improper handling of user input could potentially lead to script injection or manipulation of content. The CVSS v3.1 base score is 6.1, reflecting a medium severity level with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), scope changed (S:C), and low impact on confidentiality and integrity (C:L/I:L) but no impact on availability (A:N). The vulnerability allows attackers to modify post metadata, which could be leveraged to alter event information, inject malicious content, or manipulate site behavior. Although no known exploits are currently reported in the wild, the vulnerability's presence in a popular WordPress plugin used for event management makes it a significant concern. The scope change (S:C) indicates that the vulnerability affects resources beyond the initially vulnerable component, potentially impacting other parts of the WordPress site. The requirement for user interaction (UI:R) suggests that the attacker must trick a user into performing an action, such as visiting a crafted URL or page, to exploit the vulnerability. However, no authentication is needed, which lowers the barrier for exploitation. Overall, this vulnerability represents a moderate risk that could lead to unauthorized content manipulation and potential further exploitation through chained attacks.

For European organizations using WordPress sites with the EventON Premium or EventON plugins, this vulnerability poses a risk of unauthorized modification of event-related content. EventON is commonly used for event calendars and scheduling, which are critical for many businesses, educational institutions, and public organizations. An attacker exploiting this vulnerability could alter event details, inject misleading or malicious content, or disrupt event communications, potentially damaging organizational reputation and trust. In sectors such as government, healthcare, and finance, where accurate event information is crucial, such manipulation could lead to operational disruptions or misinformation. Furthermore, the ability to update post metadata without authorization could be leveraged as a foothold for more advanced attacks, including cross-site scripting or privilege escalation, especially if combined with other vulnerabilities. Given the widespread use of WordPress in Europe and the popularity of EventON plugins, the vulnerability could affect a broad range of organizations, from small businesses to large enterprises. The medium CVSS score reflects a moderate but tangible threat that requires timely attention to prevent exploitation.

1. Immediate update of the EventON Premium plugin to version 4.5.6 or later, and the EventON plugin to version 2.2.8 or later, where the authorization checks have been implemented. 2. If immediate patching is not possible, implement Web Application Firewall (WAF) rules to detect and block suspicious AJAX requests targeting the vulnerable endpoints. 3. Review and restrict AJAX endpoints in WordPress to ensure that only authenticated and authorized users can perform sensitive actions. 4. Conduct a thorough audit of post metadata changes and event content to identify any unauthorized modifications that may have occurred prior to patching. 5. Educate site administrators and users about phishing and social engineering risks, as exploitation requires user interaction. 6. Implement Content Security Policy (CSP) headers to mitigate potential cross-site scripting attacks that could be chained with this vulnerability. 7. Regularly monitor security advisories related to EventON and WordPress plugins to stay informed about new vulnerabilities and patches. 8. Consider isolating critical event management functions or using alternative plugins with a strong security track record if patching is delayed.