CVE-2024-13505 is a stored cross-site scripting (XSS) vulnerability classified under CWE-79, affecting the ays-pro Survey Maker plugin for WordPress in all versions up to and including 5.1.3.3. The vulnerability stems from insufficient sanitization and escaping of user input in the 'ays_sections[5][questions][8][title]' parameter during web page generation. This flaw allows authenticated attackers with administrator-level access to inject arbitrary JavaScript code into survey pages. When other users view these pages, the injected scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or data exfiltration. The vulnerability is limited to multi-site WordPress installations where the 'unfiltered_html' capability is disabled, which restricts HTML content filtering. The CVSS 3.1 base score is 5.5, reflecting a medium severity due to the requirement for high privileges (administrator) and no user interaction needed for exploitation. The attack vector is network-based, and the scope is changed because the vulnerability affects other users beyond the attacker. No public exploits have been reported yet, but the risk remains significant given the administrative access needed to exploit it. The vulnerability highlights the importance of proper input validation and output encoding in WordPress plugins, especially those handling complex input structures like surveys.

The primary impact of CVE-2024-13505 is the potential for stored XSS attacks that can compromise the confidentiality and integrity of user sessions and data within affected WordPress multi-site environments. An attacker with administrator privileges can inject malicious scripts that execute in the context of other users, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of victims. This can undermine trust in the affected websites and lead to reputational damage, data breaches, and compliance violations. Although exploitation requires high privileges, the widespread use of WordPress and the Survey Maker plugin in multi-site configurations means that organizations hosting multiple sites or clients on a single WordPress instance are at risk. The vulnerability does not impact availability directly but can facilitate further attacks that degrade service or compromise system integrity.

To mitigate CVE-2024-13505, organizations should first update the ays-pro Survey Maker plugin to a version that addresses this vulnerability once available. In the absence of an official patch, administrators should restrict administrator access to trusted personnel only and audit existing administrator accounts for suspicious activity. Additionally, enabling the 'unfiltered_html' capability where feasible can reduce the attack surface, although this may have other security implications and should be evaluated carefully. Implementing a Web Application Firewall (WAF) with rules to detect and block suspicious script injection attempts targeting the vulnerable parameter can provide interim protection. Regularly scanning WordPress installations with security plugins that detect XSS vulnerabilities and monitoring logs for unusual behavior are also recommended. Finally, educating administrators about the risks of stored XSS and enforcing the principle of least privilege can limit exploitation opportunities.