CVE-2025-59593 identifies a stored cross-site scripting (XSS) vulnerability in the Colibri Page Builder plugin developed by Extend Themes, affecting versions prior to 1.0.334. The vulnerability is caused by improper neutralization of user-supplied input during the generation of web pages, which allows malicious scripts to be stored and subsequently executed in the context of users viewing the affected pages. This type of vulnerability can be exploited by an attacker with at least low-level privileges (PR:L) and requires user interaction (UI:R), such as a victim visiting a maliciously crafted page. The vulnerability impacts confidentiality and integrity by potentially allowing theft of session cookies, defacement, or unauthorized actions performed on behalf of the victim. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) indicates network attack vector, low attack complexity, partial privileges required, user interaction needed, scope change, and limited confidentiality and integrity impact without affecting availability. No known exploits have been reported in the wild as of the publication date (October 22, 2025). The vulnerability affects WordPress sites using the Colibri Page Builder plugin, a popular tool for building and customizing websites. Since stored XSS can persist and affect multiple users, it poses a significant risk especially on sites with multiple contributors or user-generated content. The lack of a patch link suggests that a fix may be pending or recently released, so users should monitor vendor advisories closely.

For European organizations, this vulnerability can lead to unauthorized access to user sessions, data leakage, and potential defacement or manipulation of website content. This can damage brand reputation, lead to regulatory non-compliance (e.g., GDPR breaches if personal data is exposed), and facilitate further attacks such as phishing or malware distribution. Organizations relying on Colibri Page Builder for public-facing websites or intranet portals are particularly at risk. The medium severity reflects that while the vulnerability requires some privileges and user interaction, the potential for scope change and compromise of confidentiality and integrity is significant. Attackers could leverage this vulnerability to escalate privileges or move laterally within an organization’s web infrastructure. Additionally, stored XSS can affect multiple users, amplifying the impact. Given the widespread use of WordPress in Europe, the threat is relevant to a broad range of sectors including e-commerce, government, education, and media.

1. Immediately monitor for updates from Extend Themes and apply patches for Colibri Page Builder as soon as they are released. 2. Restrict plugin usage to trusted administrators and limit user privileges to the minimum necessary to reduce the risk of malicious input. 3. Implement robust input validation and output encoding on all user-generated content within the website to prevent injection of malicious scripts. 4. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 5. Conduct regular security audits and penetration testing focusing on web application vulnerabilities, including stored XSS. 6. Monitor web server and application logs for unusual activities indicative of exploitation attempts. 7. Educate content editors and administrators about the risks of XSS and safe content management practices. 8. Consider using Web Application Firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting WordPress plugins. 9. Backup website data regularly to enable quick restoration in case of compromise. 10. Review and harden WordPress security configurations, including disabling unnecessary plugins and themes.