CVE-2025-59593 is a Stored Cross-Site Scripting (XSS) vulnerability identified in the Colibri Page Builder plugin developed by Extend Themes for WordPress. This vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, allowing malicious scripts to be stored persistently within the website's content. When a victim visits a compromised page, the injected script executes in their browser context, potentially leading to session hijacking, theft of sensitive data, unauthorized actions on behalf of the user, or delivery of malware. The vulnerability affects all versions of Colibri Page Builder prior to 1.0.334. No authentication or special user interaction beyond visiting the affected page is required to exploit this flaw, increasing its risk profile. Although no public exploits have been reported yet, the nature of stored XSS makes it a critical concern for websites relying on this plugin. The vulnerability was reserved in September 2025 and published in October 2025, but no official patches or CVSS score have been released at the time of this analysis. Stored XSS vulnerabilities are particularly dangerous because they can affect multiple users and persist until remediated. The Colibri Page Builder plugin is widely used in WordPress environments to create and manage web page layouts, making the scope of affected systems potentially broad. Attackers could leverage this vulnerability to compromise site visitors, deface websites, or pivot into deeper network attacks if administrative users are targeted. The absence of patches necessitates immediate attention to alternative mitigations and monitoring.

For European organizations, this vulnerability poses a significant threat to the confidentiality, integrity, and availability of their web assets. Exploitation could lead to unauthorized access to user sessions, leakage of sensitive information such as credentials or personal data, and unauthorized actions performed on behalf of legitimate users. This can result in reputational damage, regulatory non-compliance (e.g., GDPR violations), and financial losses. Websites compromised via this vulnerability could be used to distribute malware or phishing content, further amplifying the impact. Since Colibri Page Builder is a popular WordPress plugin, organizations relying on it for their web presence, including e-commerce, government portals, and corporate sites, are at risk. The persistent nature of stored XSS means that once exploited, the malicious code can affect multiple visitors over time until the vulnerability is addressed. The lack of a patch increases the window of exposure, making proactive mitigation critical. Additionally, attackers could target administrative users to gain deeper access, potentially leading to full site compromise or lateral movement within organizational networks.

1. Monitor official Extend Themes channels and Patchstack for the release of a security patch and apply it immediately upon availability. 2. Until a patch is available, implement strict input validation and sanitization on all user inputs related to the Colibri Page Builder, possibly via web application firewalls (WAF) or custom filters. 3. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of any injected code. 4. Conduct regular security audits and scanning of websites using Colibri Page Builder to detect any injected malicious scripts or anomalies. 5. Limit administrative access and enforce multi-factor authentication to reduce the risk of attackers leveraging stolen sessions. 6. Educate site administrators and developers about the risks of XSS and safe coding practices to prevent similar vulnerabilities. 7. Consider temporarily disabling or replacing the Colibri Page Builder plugin with alternative solutions if immediate patching is not feasible. 8. Maintain regular backups of website data to enable quick restoration in case of compromise.