CVE-2024-11870 is a stored cross-site scripting (XSS) vulnerability identified in the Event Registration Calendar By vcita plugin for WordPress, affecting all versions up to and including 1.4.0. The root cause is insufficient sanitization and output escaping of user-supplied attributes within the plugin's shortcodes. This flaw allows authenticated attackers with contributor-level privileges or higher to inject arbitrary JavaScript code into pages generated by the plugin. When other users access these pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the WordPress site. The vulnerability is classified under CWE-79, highlighting improper neutralization of input during web page generation. The CVSS 3.1 base score is 6.4, reflecting a medium severity level, with an attack vector of network, low attack complexity, and requiring privileges but no user interaction. The scope is changed, indicating that the vulnerability affects components beyond the initially vulnerable plugin, potentially impacting the broader WordPress environment. No public exploits have been reported yet, but the risk remains significant due to the widespread use of WordPress and the plugin. The vulnerability emphasizes the importance of robust input validation and output encoding in web applications, especially for plugins that accept user-generated content or attributes.

The primary impact of CVE-2024-11870 is on the confidentiality and integrity of affected WordPress sites using the Event Registration Calendar By vcita plugin. Successful exploitation allows attackers to execute arbitrary scripts in the context of the victim's browser, which can lead to theft of authentication cookies, session tokens, or other sensitive information. This can enable attackers to impersonate legitimate users, escalate privileges, or perform unauthorized actions such as content manipulation or further malware distribution. Although the vulnerability does not directly affect availability, the resulting compromise can lead to site defacement or loss of user trust. Organizations relying on this plugin for event registration and calendar management face risks of data leakage and reputational damage. The requirement for contributor-level access limits exploitation to insiders or compromised accounts, but this level of access is common in collaborative WordPress environments, increasing the attack surface. The vulnerability's scope change suggests potential cascading effects on other site components, amplifying the risk. Given the widespread use of WordPress globally, many organizations, including small businesses, educational institutions, and non-profits, could be affected if they use this plugin without patching.

To mitigate CVE-2024-11870, organizations should first check for and apply any official patches or updates released by vcita that address this vulnerability. If no patch is available, administrators should consider temporarily disabling the Event Registration Calendar plugin or restricting contributor-level access until a fix is applied. Implement strict user role management to limit the number of users with contributor or higher privileges. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious shortcode attribute inputs that may contain script tags or JavaScript event handlers. Conduct regular security audits of WordPress plugins and monitor logs for unusual shortcode usage or injection attempts. Educate content contributors about safe input practices and the risks of injecting untrusted content. Additionally, site owners can implement Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of XSS attacks. Finally, consider using security plugins that provide enhanced input sanitization and output encoding for shortcodes and user-generated content.