CVE-2024-8861 is a stored cross-site scripting vulnerability identified in the ProfileGrid – User Profiles, Groups and Communities plugin for WordPress, affecting all versions up to and including 5.9.3.2. The root cause is the improper use of the WordPress function wp_kses_allowed_html, which is intended to sanitize HTML input by restricting allowed tags and attributes. However, in this case, the 'onclick' attribute is permitted on certain HTML elements without sufficient context validation or restriction, enabling authenticated users with Contributor-level access or higher to inject arbitrary JavaScript code into user profile pages or community group pages. When other users visit these pages, the injected scripts execute in their browsers, potentially allowing attackers to steal cookies, hijack sessions, perform actions on behalf of victims, or conduct further attacks such as phishing or malware delivery. The vulnerability requires authentication but no user interaction beyond page access. The CVSS 3.1 base score is 6.4, indicating medium severity, with an attack vector of network, low attack complexity, privileges required at the Contributor level, no user interaction, and a scope change due to affecting other users. No public exploits have been reported yet, but the vulnerability poses a significant risk to WordPress sites using this plugin, especially those with multiple contributors and active user communities. The vulnerability highlights the importance of strict input sanitization and attribute whitelisting in web applications, particularly in user-generated content contexts.

The impact of CVE-2024-8861 on organizations worldwide can be significant, especially for those relying on WordPress sites with the ProfileGrid plugin for managing user profiles, groups, and communities. Successful exploitation allows attackers to execute arbitrary scripts in the context of other users, potentially leading to session hijacking, credential theft, unauthorized actions, and data exposure. This compromises confidentiality and integrity of user data and can damage organizational reputation. Since the vulnerability requires only Contributor-level access, attackers can leverage compromised or legitimate contributor accounts to escalate their impact. The scope of the attack affects all users who view the injected pages, increasing the potential victim pool. While availability is not directly impacted, secondary effects such as account lockouts or site defacement could occur. Organizations with active user communities, membership sites, or collaborative platforms are at higher risk. The lack of known exploits in the wild currently reduces immediate threat but does not eliminate the risk of future exploitation. Failure to address this vulnerability could lead to targeted attacks, data breaches, and regulatory compliance issues related to user data protection.

To mitigate CVE-2024-8861, organizations should first update the ProfileGrid plugin to a patched version once released by the vendor. Until a patch is available, administrators should restrict Contributor-level access to trusted users only, minimizing the risk of malicious script injection. Implement additional input validation and sanitization on user-submitted content, especially for HTML attributes like 'onclick', by using stricter custom filters or disabling risky attributes entirely. Employ a Web Application Firewall (WAF) with rules designed to detect and block XSS payloads targeting the affected plugin. Regularly audit user-generated content for suspicious scripts or injected code. Educate users and administrators about the risks of XSS and the importance of cautious privilege assignment. Monitor logs for unusual activity related to profile or group page edits. Consider disabling the ProfileGrid plugin temporarily if the risk is unacceptable and no patch is available. Finally, implement Content Security Policy (CSP) headers to restrict script execution sources, reducing the impact of any injected scripts.