CVE-2024-11685 is a reflected Cross-Site Scripting (XSS) vulnerability identified in the 'Kudos Donations – Easy donations and payments with Mollie' WordPress plugin developed by iseardmedia. This vulnerability affects all plugin versions up to and including 3.2.9. The root cause is the improper neutralization of user input during web page generation, specifically due to the use of the WordPress function add_query_arg without appropriate escaping of URL parameters. This flaw allows an unauthenticated attacker to craft malicious URLs containing arbitrary JavaScript code. When a victim clicks such a link, the injected script executes in their browser context, potentially leading to theft of cookies, session tokens, or other sensitive information, as well as manipulation of the displayed content. The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation). The CVSS v3.1 base score is 6.1, indicating a medium severity level, with attack vector as network (remote), low attack complexity, no privileges required, but requiring user interaction. The scope is changed (S:C) because the vulnerability can affect resources beyond the vulnerable component, such as user sessions or other site data. No patches or fixes are currently linked, and no known exploits have been reported in the wild as of the publication date (November 28, 2024).

The primary impact of this vulnerability is on the confidentiality and integrity of user data. Successful exploitation can lead to theft of authentication cookies or tokens, enabling session hijacking and unauthorized actions on behalf of the victim. It can also facilitate phishing attacks by modifying web page content to deceive users. While availability is not directly affected, the reputational damage and potential data breaches can be significant for organizations relying on this plugin for donations and payments. Since the plugin is used in WordPress environments, which power a large portion of websites globally, the attack surface is considerable. Organizations processing financial transactions or donations are particularly at risk, as attackers could leverage this vulnerability to redirect payments or harvest donor information. The requirement for user interaction (clicking a malicious link) somewhat limits the ease of exploitation but does not eliminate the risk, especially in environments with high user traffic or where social engineering is feasible.

Organizations should immediately check if they are using the 'Kudos Donations – Easy donations and payments with Mollie' plugin and verify the version. Since no official patch links are currently available, administrators should consider the following mitigations: 1) Temporarily disable or remove the plugin until a patched version is released. 2) Implement Web Application Firewall (WAF) rules to detect and block suspicious query parameters or scripts in URLs targeting the plugin endpoints. 3) Educate users and administrators about the risks of clicking unsolicited links, especially those related to donation or payment pages. 4) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected pages. 5) Monitor web logs for unusual URL patterns or spikes in traffic that may indicate exploitation attempts. 6) Once a patch is released, prioritize timely updates to the plugin. 7) Review and sanitize all user inputs and URL parameters in custom code or themes interacting with the plugin to prevent similar issues.