CVE-2025-3527 is a security vulnerability identified in the EventON Pro plugin for WordPress, a widely used virtual event calendar plugin. The vulnerability stems from a missing authorization check (CWE-862) in the 'assets/lib/settings/settings.js' file affecting all versions up to and including 4.9.6. This flaw allows authenticated users with as low as Subscriber-level privileges to inject arbitrary web scripts into pages managed by the plugin. These injected scripts execute whenever any user accesses the compromised page, enabling potential cross-site scripting (XSS) attacks. The vulnerability was partially addressed in version 4.9.6, but no complete patch is indicated. The CVSS 3.1 base score is 6.4 (medium severity), reflecting that the attack vector is network-based, requires low attack complexity, and only low privileges (authenticated user) are needed, with no user interaction required. The impact affects confidentiality and integrity, as attackers can execute arbitrary scripts, potentially stealing session tokens, modifying content, or performing actions on behalf of other users. The scope is changed since the vulnerability affects multiple users on the same site. No known exploits are reported in the wild yet, but the vulnerability presents a significant risk to WordPress sites using this plugin, especially those with multiple user roles and public-facing event pages.

For European organizations, this vulnerability poses a moderate risk, particularly for those relying on WordPress sites with the EventON Pro plugin for event management and communication. Exploitation could lead to unauthorized data manipulation, session hijacking, or defacement, undermining user trust and potentially exposing sensitive user information. Organizations in sectors such as education, public administration, and event management, which often use WordPress for their web presence, could face reputational damage and compliance issues under GDPR if personal data is compromised. The ability for low-privilege users to inject scripts increases the attack surface, especially in environments with many registered users or where subscriber accounts are easily obtained. The lack of a complete patch means organizations must be vigilant and proactive in mitigating risks.

1. Immediate upgrade: Organizations should verify if a newer, fully patched version of EventON Pro beyond 4.9.6 is available and apply it promptly. 2. Access control review: Restrict Subscriber-level and other low-privilege user registrations to trusted individuals only, or disable user registrations if not needed. 3. Web application firewall (WAF): Deploy WAF rules to detect and block suspicious script injection attempts targeting the plugin's endpoints. 4. Content Security Policy (CSP): Implement strict CSP headers to limit the execution of unauthorized scripts on affected pages. 5. Monitoring and logging: Enable detailed logging of user actions and monitor for unusual script injection patterns or page modifications. 6. Plugin alternatives: Consider replacing EventON Pro with alternative calendar plugins that have a stronger security track record if patching is delayed. 7. User education: Inform site administrators and users about the risks of low-privilege account misuse and encourage strong password policies to prevent account compromise.