CVE-2025-11802 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Bulma Shortcodes plugin for WordPress, specifically in the handling of the 'type' attribute within the bulma-notification shortcode. This vulnerability stems from insufficient sanitization of user-supplied input and inadequate escaping of output before rendering on web pages. As a result, authenticated users with contributor-level access or higher can inject arbitrary JavaScript code into pages or posts. When other users access these pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the context of the affected site. The vulnerability affects all versions up to and including 1.0 of the plugin. The CVSS v3.1 score of 6.4 reflects a medium severity rating, with an attack vector over the network, low attack complexity, privileges required at the contributor level, no user interaction needed, and a scope change due to the impact on other users. The confidentiality and integrity of user data can be partially compromised, although availability is not impacted. No public exploits have been reported to date, but the vulnerability is publicly disclosed and should be addressed promptly. The root cause is the failure to properly neutralize input during web page generation, classified under CWE-79. This vulnerability highlights the importance of rigorous input validation and output encoding in WordPress plugin development to prevent stored XSS attacks.

The primary impact of this vulnerability is the potential for attackers with contributor-level access to inject persistent malicious scripts into web pages, which execute in the browsers of any users viewing those pages. This can lead to theft of session cookies, enabling account takeover or privilege escalation, unauthorized actions performed on behalf of users, and exposure of sensitive information. While availability is not affected, the compromise of confidentiality and integrity can damage user trust, lead to data breaches, and cause reputational harm to organizations. Since WordPress powers a significant portion of the web, sites using the Bulma Shortcodes plugin are at risk, especially those with multiple contributors. Attackers could leverage this vulnerability to target site administrators or editors, potentially gaining further control over the site or its content. The scope of impact extends beyond the initial contributor, affecting all users who access the injected content. Organizations relying on this plugin for content presentation may face compliance issues if user data is exposed or manipulated. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits following public disclosure.

Organizations should immediately verify if they use the Bulma Shortcodes plugin and identify the affected versions (all up to 1.0). Since no official patch links are currently available, administrators should consider temporarily disabling the plugin or restricting contributor-level access until a fix is released. Implement strict input validation on the 'type' shortcode attribute, ensuring only expected values are accepted, and apply robust output encoding to neutralize any injected scripts. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious shortcode inputs or script injections. Regularly audit user permissions to minimize the number of contributors and enforce the principle of least privilege. Monitor site content for unauthorized changes or injected scripts. Educate contributors about safe content practices and the risks of injecting untrusted code. Once a vendor patch is released, apply it promptly. Additionally, consider using security plugins that scan for XSS vulnerabilities and malicious content. Backup site data regularly to enable recovery in case of compromise.