CVE-2025-66024 is a stored Cross-Site Scripting (XSS) vulnerability identified in the XWiki blog application component (application-blog-ui) maintained by xwiki-contrib. The vulnerability affects all versions prior to 9.15.7. It arises because the blog post title is directly embedded into the HTML <title> tag without proper input sanitization or escaping, violating secure coding practices against CWE-79 (Improper Neutralization of Input During Web Page Generation). An attacker who has authenticated permissions to create or edit blog posts can inject malicious JavaScript code into the title field. This malicious script is then stored on the server and served to any user who views the blog post, including high-privilege users such as administrators. Upon viewing, the script executes in the victim's browser context, enabling attacks such as session hijacking, cookie theft, or privilege escalation through unauthorized actions performed with the victim's credentials. The vulnerability does not require elevated privileges beyond blog post editing rights but does require user interaction to trigger the payload. The issue was addressed in version 9.15.7 by implementing proper escaping of the title field before rendering it in the HTML <title> tag, effectively neutralizing the injected scripts. No alternative mitigations or workarounds are available, emphasizing the need for prompt patching. The CVSS v4.0 base score is 8.6 (high severity), reflecting the network attack vector, low attack complexity, no required privileges beyond editing, and high impact on confidentiality, integrity, and availability.

The exploitation of this vulnerability can have severe consequences for organizations using vulnerable versions of the XWiki blog application. Attackers with blog post editing permissions can inject persistent malicious scripts that execute in the browsers of users viewing the blog posts, including administrators. This can lead to session hijacking, allowing attackers to impersonate legitimate users and gain unauthorized access to sensitive information or administrative functions. Privilege escalation is also possible if attackers leverage the XSS to perform actions on behalf of high-privilege users. The compromise of administrative accounts can result in further system manipulation, data exfiltration, or deployment of additional malware. Since the vulnerability is stored and persistent, it can affect multiple users over time, increasing the attack surface. Organizations relying on XWiki for collaboration or content management may face reputational damage, data breaches, and operational disruptions if exploited. The lack of known exploits in the wild currently reduces immediate risk but does not diminish the potential impact if attackers develop weaponized payloads.

To mitigate this vulnerability, organizations should immediately upgrade the XWiki blog application to version 9.15.7 or later, where the issue has been patched by implementing proper escaping of the blog post title. Since no workarounds exist, patching is the primary and most effective defense. Additionally, organizations should review and restrict permissions to create or edit blog posts to trusted users only, minimizing the risk of malicious content injection. Implementing Content Security Policy (CSP) headers can help limit the impact of XSS by restricting the execution of unauthorized scripts. Regular security audits and code reviews of custom XWiki extensions or plugins should be conducted to detect similar injection flaws. Monitoring logs and user activity for unusual behavior related to blog post creation or editing can help detect attempted exploitation. Educating users about the risks of clicking on suspicious links or viewing untrusted content within the platform can reduce the likelihood of successful attacks. Finally, organizations should maintain up-to-date backups to recover quickly in case of compromise.