Unrestricted File Upload Vulnerability in ResponsiveFilemanager

A critical security vulnerability (CVE-2026-18788) exists in Trippo ResponsiveFilemanager versions up to 9.14.0. The vulnerability resides within the filemanager/dialog.php script and permits an unauthenticated, remote attacker to perform unrestricted file uploads. Because the vendor has provided no response and the software is no longer supported, this flaw will remain unpatched, exposing environments that continue to run this legacy component. Publicly available exploit code exists, increasing the risk of exploitation. Defenders should prioritize identifying instances of ResponsiveFilemanager in their environments and replacing the legacy file management component, as no security updates will be issued for this software.

Attack Chain

1. Attacker performs reconnaissance to identify web servers running Trippo ResponsiveFilemanager.
2. Attacker interacts with the publicly accessible filemanager/dialog.php endpoint.
3. Attacker crafts a malicious HTTP POST request targeting the file upload functionality.
4. Attacker bypasses missing or inadequate file type validation mechanisms within the script.
5. Attacker uploads a malicious script (e.g., a web shell) to a web-accessible directory.
6. Attacker confirms the location of the uploaded file via server responses or directory traversal.
7. Attacker executes the uploaded script by requesting the file directly via the web server.
8. Attacker gains persistent remote code execution (RCE) on the underlying host.

Impact

Successful exploitation allows remote attackers to gain full control over the web server by uploading and executing arbitrary web shells. This leads to complete compromise of the web application, potential lateral movement within the network, and exfiltration of sensitive configuration or user data. Given the product's age and lack of support, affected organizations are likely to remain permanently vulnerable unless the software is removed or replaced.

Recommendation

• Identify and audit all web applications using ResponsiveFilemanager versions 9.14.0 or older.
• Restrict network access to the filemanager/ directory via web server configuration (e.g., Nginx, Apache) to authorized internal IP ranges only.
• Remove the ResponsiveFilemanager component entirely if it is not business-critical, as no patch for CVE-2026-18788 will be released.
• Monitor web server logs for HTTP POST requests to dialog.php originating from suspicious or external IP addresses.