CVE-2025-11747 is a stored cross-site scripting (XSS) vulnerability identified in the Colibri Page Builder plugin for WordPress, a popular tool used to design and manage website pages. The vulnerability arises from improper neutralization of input during web page generation, specifically within the colibri_blog_posts shortcode. This shortcode fails to adequately sanitize and escape user-supplied attributes, allowing an attacker with contributor-level or higher privileges to inject arbitrary JavaScript code into pages. Because the malicious script is stored persistently in the page content, it executes whenever any user accesses the affected page, potentially compromising user sessions, stealing cookies, or performing actions on behalf of the user. The vulnerability affects all versions up to and including 1.0.345. The CVSS 3.1 base score of 6.4 reflects a medium severity, with an attack vector of network, low attack complexity, requiring privileges (PR:L), no user interaction, and scope change (S:C), impacting confidentiality and integrity but not availability. No public exploits have been reported yet, but the vulnerability poses a significant risk in environments where multiple users have contributor or higher access. The root cause is insufficient input validation and output encoding in the plugin's handling of shortcode attributes, a common issue in web application security. This vulnerability highlights the need for secure coding practices in WordPress plugin development, especially for plugins that allow user-generated content to be rendered dynamically.

For European organizations, this vulnerability can lead to unauthorized script execution within their WordPress sites, potentially resulting in session hijacking, data theft, defacement, or unauthorized actions performed with the privileges of affected users. Organizations with multi-user WordPress environments, such as media companies, educational institutions, and e-commerce platforms, are particularly at risk. The compromise of contributor accounts could allow attackers to escalate their influence by injecting malicious scripts that affect administrators or visitors. This can damage organizational reputation, lead to data breaches involving personal or sensitive information, and disrupt business operations. Although availability is not directly impacted, the integrity and confidentiality of web content and user data are at risk. Given the widespread use of WordPress across Europe, the vulnerability could have a broad impact if exploited at scale. The lack of known exploits currently provides a window for proactive mitigation, but the medium severity score indicates that exploitation could have meaningful consequences.

European organizations should immediately audit their WordPress installations to identify the presence of the Colibri Page Builder plugin and verify its version. Until an official patch is released, restrict contributor-level and higher privileges to trusted users only, minimizing the risk of malicious input. Implement additional input validation and output encoding at the web application firewall (WAF) or reverse proxy level to detect and block suspicious shortcode attribute payloads. Regularly monitor logs and user activity for unusual behavior indicative of exploitation attempts. Educate content contributors about safe content practices and the risks of injecting untrusted code. Once patches or updates become available from the vendor, apply them promptly. Consider deploying Content Security Policy (CSP) headers to limit the execution of unauthorized scripts. Additionally, conduct periodic security assessments and penetration tests focusing on plugin vulnerabilities to proactively identify and remediate similar issues.