CVE-2025-13841 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79 affecting the Smart App Banners plugin for WordPress developed by clevelandwebdeveloper. The vulnerability arises from improper neutralization of input during web page generation, specifically in the 'size' and 'verticalalign' parameters of the 'app-store-download' shortcode. All versions up to and including 1.2 are affected due to insufficient sanitization and output escaping of these user-supplied attributes. An attacker with authenticated Contributor-level access or higher can inject arbitrary JavaScript code that is stored persistently in the WordPress database and executed in the context of any user who views the infected page. This can lead to session hijacking, privilege escalation, or unauthorized actions performed on behalf of users. The vulnerability has a CVSS 3.1 base score of 6.4, indicating medium severity, with an attack vector of network (remote), low attack complexity, requiring privileges (Contributor or above), no user interaction, and a scope change due to affecting other components. No known public exploits or patches are currently available, increasing the urgency for organizations to implement interim mitigations. The vulnerability impacts the confidentiality and integrity of user sessions and data but does not affect availability. Since WordPress is widely used across Europe, and this plugin is popular for app promotion banners, the risk is significant for websites with multiple contributors or public content management workflows.

For European organizations, this vulnerability poses a moderate risk primarily to websites using the Smart App Banners plugin on WordPress, especially those with multiple contributors or editors who have Contributor-level access or higher. Exploitation could allow attackers to inject malicious scripts that execute in the browsers of site visitors or administrators, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions such as content modification or privilege escalation. This can damage organizational reputation, lead to data breaches, and disrupt business operations. Public-facing websites, e-commerce platforms, and portals that rely on WordPress and this plugin are particularly vulnerable. The impact is heightened in sectors with strict data protection regulations like GDPR, where any compromise of user data or site integrity can result in legal and financial penalties. Although no known exploits are currently active, the presence of this vulnerability in a widely deployed CMS plugin means that attackers may develop exploits, increasing the risk over time.

1. Immediately audit WordPress sites for the presence of the Smart App Banners plugin and identify versions up to 1.2. 2. Restrict Contributor-level and higher user privileges to trusted personnel only, minimizing the risk of malicious shortcode attribute injection. 3. Implement custom input validation and output escaping for the 'size' and 'verticalalign' shortcode parameters via WordPress hooks or security plugins to sanitize user input before rendering. 4. Temporarily disable or remove the Smart App Banners plugin if feasible until an official patch is released by the vendor. 5. Monitor website content for suspicious shortcode usage or unexpected script injections. 6. Educate content contributors about safe usage practices and the risks of injecting untrusted content. 7. Employ Web Application Firewalls (WAFs) with rules targeting XSS payloads in shortcode parameters to block exploitation attempts. 8. Keep WordPress core and all plugins updated and subscribe to vulnerability advisories for timely patching once available.