CVE-2025-3527 is a vulnerability classified under CWE-862 (Missing Authorization) found in the EventON Pro plugin for WordPress, a widely used virtual event calendar solution. The root cause is a missing capability check in the 'assets/lib/settings/settings.js' file, which fails to properly verify user permissions before allowing modifications to plugin data. This flaw enables authenticated users with Subscriber-level privileges or higher to inject arbitrary JavaScript code into pages managed by the plugin. Because the injected scripts execute whenever any user accesses the compromised pages, this leads to persistent cross-site scripting (XSS) attacks. The vulnerability affects all versions of EventON Pro up to and including 4.9.6, with a partial patch introduced in version 4.9.6, indicating that some risk remains if the patch is not fully applied or if older versions are still in use. Exploitation requires no user interaction beyond the attacker’s own authenticated session, but does require at least low-level access, which is commonly available to registered users on many WordPress sites. The vulnerability does not impact availability but compromises confidentiality and integrity by enabling script injection that can steal session tokens, deface content, or perform unauthorized actions on behalf of users. No known exploits have been reported in the wild so far, but the presence of this vulnerability in a popular plugin makes it a notable risk for WordPress sites using EventON Pro. The CVSS v3.1 base score is 6.4, reflecting a medium severity level due to network attack vector, low attack complexity, and partial privileges required.

The primary impact of CVE-2025-3527 is the unauthorized injection of malicious scripts by low-privileged authenticated users, leading to persistent XSS attacks. This can result in session hijacking, theft of sensitive user data, unauthorized actions performed on behalf of users, and potential defacement of event calendar pages. For organizations, this undermines the integrity and confidentiality of their websites and user data, potentially damaging reputation and trust. Since WordPress powers a significant portion of the web, and EventON Pro is a popular plugin for event management, the vulnerability could affect a wide range of sectors including education, corporate events, entertainment, and government portals. The requirement for authenticated access limits the attack surface somewhat, but many sites allow user registrations at Subscriber level or higher, making exploitation feasible. Persistent XSS can also be leveraged as a foothold for further attacks within the network or to distribute malware to site visitors. The lack of availability impact means the site remains operational, potentially allowing prolonged exploitation if unnoticed.

Organizations should immediately verify the version of EventON Pro installed and upgrade to the latest version beyond 4.9.6 where the vulnerability is fully patched. If an upgrade is not immediately possible, implement strict user role management to limit Subscriber-level access and above only to trusted users. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious script injection attempts targeting the plugin's endpoints. Conduct thorough code reviews and penetration testing focused on plugin functionality to detect any residual authorization issues. Monitor web server and application logs for unusual activity or script injection patterns. Educate site administrators and users about the risks of XSS and the importance of applying security updates promptly. Consider disabling or replacing the EventON Pro plugin if it is not critical to operations until a secure version is confirmed. Additionally, implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected pages.