CVE-2024-11878 is a stored cross-site scripting vulnerability classified under CWE-79, found in the Category Post Slider plugin for WordPress developed by gbsdeveloper. The vulnerability arises from improper neutralization of input during web page generation, specifically in the handling of the 'category-post-slider' shortcode attributes. All versions up to and including 1.4 are affected. Authenticated users with contributor-level permissions or higher can inject arbitrary JavaScript code via crafted shortcode attributes due to insufficient input sanitization and output escaping. When a page containing the malicious shortcode is viewed, the injected script executes in the context of the victim's browser, potentially compromising user sessions, stealing credentials, or performing unauthorized actions on behalf of the user. The vulnerability has a CVSS 3.1 base score of 6.4, indicating medium severity, with an attack vector of network, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with a scope change. 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. The lack of a patch link suggests that a fix may not yet be available, emphasizing the need for immediate mitigation steps.

The exploitation of this vulnerability can lead to unauthorized script execution in the browsers of users visiting affected pages, resulting in session hijacking, credential theft, defacement, or the spread of malware. For organizations, this can mean compromised user accounts, loss of trust, data breaches, and potential regulatory penalties. Since the vulnerability requires contributor-level access, attackers must first gain some level of authenticated access, which may be easier in environments with many contributors or weak access controls. The scope change in the CVSS vector indicates that the vulnerability can affect resources beyond the initially compromised component, potentially impacting the entire WordPress site and its users. This can disrupt business operations, damage brand reputation, and increase incident response costs. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate it, as attackers may develop exploits rapidly once the vulnerability is public. Organizations relying on the Category Post Slider plugin should consider the threat significant, especially those with high traffic or sensitive data.

1. Immediately review and restrict contributor-level access to trusted users only, minimizing the risk of malicious shortcode injection. 2. Monitor WordPress sites for unusual shortcode usage or unexpected script tags in page content. 3. Implement web application firewall (WAF) rules to detect and block suspicious shortcode attribute patterns or script injections related to the Category Post Slider plugin. 4. If possible, disable or remove the Category Post Slider plugin until a security patch is released. 5. Educate content contributors about safe content practices and the risks of injecting untrusted code. 6. Regularly back up website data to enable recovery in case of compromise. 7. Follow the plugin vendor and WordPress security advisories closely for updates or patches addressing this vulnerability. 8. Consider deploying Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on the website. 9. Conduct periodic security audits and vulnerability scans focusing on WordPress plugins and user privileges. These steps go beyond generic advice by focusing on access control, monitoring, and layered defenses tailored to this specific plugin vulnerability.