CVE-2023-6158 is a security vulnerability identified in the EventON WordPress plugin, a popular virtual event calendar solution developed by ashanjay. This vulnerability stems from a missing authorization check (CWE-862) in the function evo_eventpost_update_meta, which is responsible for updating post metadata. The flaw exists in all versions up to and including 4.5.4 for the Pro version and 2.2.7 for the free version. Because the plugin fails to verify user capabilities before allowing metadata updates, unauthenticated attackers can exploit this to modify or delete arbitrary post metadata. This can lead to unauthorized data manipulation and potential loss of data. Additionally, certain parameters involved in the exploit may allow content injection, which could be leveraged for further attacks such as cross-site scripting (XSS) or content spoofing. The vulnerability has a CVSS v3.1 base score of 6.5, indicating a medium severity level. The attack vector is network-based with no privileges or user interaction required, making exploitation relatively straightforward. However, there are no known exploits in the wild at the time of publication. The vulnerability affects the integrity and availability of data managed by the plugin but does not directly impact confidentiality. Since EventON is a widely used plugin for managing event-related content on WordPress sites, exploitation could disrupt event information, degrade user trust, or serve as a foothold for further compromise within affected websites.

For European organizations, this vulnerability poses a moderate risk primarily to websites and services that rely on the EventON plugin to manage virtual or hybrid events. Unauthorized modification or deletion of event metadata can disrupt event scheduling, attendee information, and associated content, potentially causing operational disruptions and reputational damage. Organizations in sectors such as education, conferences, cultural institutions, and corporate event management that use WordPress with EventON are particularly at risk. While the vulnerability does not directly expose sensitive personal data, the ability to inject content could be exploited to mislead users or distribute malicious payloads, increasing the risk of phishing or malware delivery. Additionally, compromised event information could affect business continuity and customer trust. Given the plugin’s network-exploitable nature without authentication, attackers can target vulnerable sites remotely, increasing the threat surface. European organizations must consider compliance implications under GDPR if the integrity of personal data related to events is compromised or if the attack leads to broader site compromise.

1. Immediate update: Organizations should promptly update the EventON plugin to a patched version once released by the vendor. Until then, consider disabling the plugin if feasible. 2. Access controls: Implement web application firewalls (WAFs) with rules to detect and block suspicious requests targeting the evo_eventpost_update_meta function or unusual POST requests to EventON endpoints. 3. Monitoring and logging: Enable detailed logging of WordPress plugin activity and monitor for unauthorized metadata changes or anomalous HTTP requests. 4. Restrict plugin usage: Limit plugin activation to only trusted administrators and restrict write permissions on the WordPress filesystem to prevent unauthorized plugin modifications. 5. Harden WordPress security: Employ multi-factor authentication for admin accounts, restrict access by IP where possible, and keep all WordPress components updated. 6. Content security policy (CSP): Implement CSP headers to mitigate potential content injection exploitation. 7. Backup and recovery: Maintain regular backups of WordPress content and metadata to enable rapid restoration in case of data loss or tampering. 8. Vendor engagement: Stay informed through vendor advisories and subscribe to vulnerability feeds to receive timely updates about patches or exploit developments.