CVE-2025-11965 is a vulnerability identified in the Eclipse Foundation's Vert.x framework, specifically affecting versions 4.0.0 through 4.5.21 and 5.0.0 through 5.0.4. The issue lies within the StaticHandler component, which is responsible for serving static files in web applications. The vulnerability stems from a misconfiguration or design flaw where the StaticHandler's setting to restrict access to hidden files does not extend to hidden directories. As a result, attackers can bypass intended access controls and retrieve files located within hidden directories, such as '.git/config', which often contain sensitive information like repository configurations, credentials, or internal project details. The vulnerability is exploitable remotely over the network without requiring authentication or user interaction, increasing its risk profile. The CVSS v4.0 score of 6.3 reflects a medium severity, considering the low attack complexity and no privileges required, but limited impact on availability and integrity. No public exploits or active exploitation have been reported as of the publication date. This vulnerability can lead to unauthorized disclosure of sensitive information, potentially aiding further attacks such as code injection, privilege escalation, or reconnaissance. The lack of patch links suggests that fixes may still be pending or in development, emphasizing the need for interim mitigations. Organizations using affected Vert.x versions in production environments should assess exposure, restrict access to hidden directories through web server configurations, and monitor for suspicious access attempts until patches are available.

For European organizations, the primary impact of CVE-2025-11965 is the potential unauthorized disclosure of sensitive internal files, which can compromise confidentiality and facilitate further attacks. Organizations relying on Vert.x for web applications or microservices may inadvertently expose hidden directories containing source code, configuration files, or credentials. This exposure can lead to intellectual property theft, leakage of sensitive business information, or provide attackers with footholds for lateral movement and privilege escalation. The impact is particularly significant for sectors with high regulatory requirements for data protection, such as finance, healthcare, and government, where data breaches can result in legal penalties and reputational damage. Additionally, organizations involved in software development or hosting critical infrastructure may face increased risk if attackers leverage exposed files to compromise build pipelines or deployment processes. Although the vulnerability does not directly affect availability or integrity, the confidentiality breach can have cascading effects on overall security posture. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once patches are released. European entities should prioritize identifying affected systems and applying mitigations to prevent data leakage and maintain compliance with data protection regulations like GDPR.

1. Upgrade Vert.x to a patched version once it becomes available from the Eclipse Foundation to address the StaticHandler access control flaw. 2. In the interim, configure web servers or reverse proxies (e.g., Nginx, Apache) to explicitly deny access to hidden directories such as those starting with a dot (e.g., '.git', '.svn'). 3. Implement strict file system permissions to restrict access to sensitive directories and files on servers hosting Vert.x applications. 4. Use application-level access controls to enforce authentication and authorization for sensitive resources. 5. Conduct thorough code and configuration reviews to identify any inadvertent exposure of hidden directories or files. 6. Monitor web server logs and application logs for unusual access patterns targeting hidden directories or files. 7. Employ web application firewalls (WAFs) with rules to block requests attempting to access hidden directories. 8. Educate development and operations teams about secure StaticHandler configuration and the risks of exposing hidden files or directories. 9. Regularly scan deployed applications for exposed sensitive files using automated tools. 10. Maintain an incident response plan to quickly address any detected unauthorized access related to this vulnerability.