CVE-2019-25673: UniSharp Laravel File Manager RCE Flaw

CVE-2019-25673 Overview

CVE-2019-25673 is an arbitrary file upload vulnerability affecting UniSharp Laravel File Manager versions v2.0.0-alpha7 and v2.0. This vulnerability allows authenticated attackers to upload malicious files by sending multipart form data to the upload endpoint. Attackers can upload PHP files with the type parameter set to Files and execute arbitrary code by accessing the uploaded file through the working directory path.

Critical Impact

Authenticated attackers can achieve remote code execution on affected servers by uploading and executing malicious PHP files through the vulnerable file manager component.

Affected Products

• UniSharp Laravel File Manager v2.0.0-alpha7
• UniSharp Laravel File Manager v2.0
• Laravel applications using vulnerable versions of the laravel-filemanager package

Discovery Timeline

• 2026-04-05 - CVE-2019-25673 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2019-25673

Vulnerability Analysis

This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The Laravel File Manager package fails to properly validate uploaded file types, allowing authenticated users to bypass intended restrictions and upload executable PHP files to the server.

The core issue stems from insufficient file type validation in the upload handler. When processing multipart form data submissions, the application does not adequately verify that uploaded files match allowed extensions or MIME types. An attacker with valid authentication credentials can craft a request that uploads a PHP webshell or other malicious script.

Once the malicious file is uploaded, it resides in a web-accessible directory. The attacker can then directly access the uploaded file via the working directory path, triggering PHP execution and achieving remote code execution with the privileges of the web server process.

Root Cause

The vulnerability exists due to improper input validation in the file upload functionality. The upload endpoint processes file submissions without enforcing strict file type restrictions, allowing dangerous file types (such as .php files) to be uploaded when the type parameter is set to Files. The lack of server-side validation of file extensions and content types enables this arbitrary file upload attack.

Attack Vector

The attack is network-based and requires the attacker to have authenticated access to the Laravel application using the vulnerable file manager. The exploitation process involves:

1. Authenticating to the target Laravel application
2. Sending a specially crafted multipart form data request to the file upload endpoint
3. Setting the type parameter to Files to bypass intended restrictions
4. Uploading a malicious PHP file (e.g., webshell)
5. Accessing the uploaded file through the known working directory path
6. Achieving arbitrary code execution on the server

The attack complexity is low as it requires no special conditions beyond authenticated access. For detailed technical information, refer to the Exploit-DB entry #46389 and the GitHub issue #356 documenting this vulnerability.

Detection Methods for CVE-2019-25673

Indicators of Compromise

• Unexpected PHP files appearing in the Laravel file manager upload directories
• Web server logs showing POST requests to /laravel-filemanager/upload with suspicious file attachments
• New files with executable extensions (.php, .phtml, .php5) in user upload directories
• Outbound connections or command execution originating from the web server process

Detection Strategies

• Monitor file upload endpoints for attempts to upload files with executable extensions
• Implement file integrity monitoring on upload directories to detect unauthorized file additions
• Review web server access logs for requests accessing unusual PHP files in upload directories
• Configure web application firewalls (WAF) to detect and block multipart requests containing PHP content

Monitoring Recommendations

• Enable detailed logging for all file upload operations in the Laravel application
• Set up alerts for file creation events in upload directories, particularly for executable file types
• Monitor for anomalous process spawning from the web server process (e.g., /bin/sh or cmd.exe)
• Implement real-time scanning of uploaded files using endpoint protection solutions

How to Mitigate CVE-2019-25673

Immediate Actions Required

• Upgrade UniSharp Laravel File Manager to the latest patched version
• Review and remove any suspicious PHP files from upload directories
• Implement strict file type validation at the application level, allowing only safe file extensions
• Configure the web server to prevent PHP execution in upload directories
• Audit authentication logs for any unauthorized access that may have exploited this vulnerability

Patch Information

Organizations should update to the latest version of the Laravel File Manager package. For detailed patch information and update instructions, refer to the official GitHub repository and the VulnCheck Advisory.

Workarounds

• Disable the file manager functionality until patching is possible
• Implement additional server-side validation to reject uploads of executable file types
• Configure .htaccess or web server rules to disable PHP execution in upload directories
• Restrict access to the file manager to trusted administrative users only

# Apache configuration to disable PHP execution in upload directory
<Directory "/path/to/laravel/storage/app/public">
    php_admin_flag engine Off
    RemoveHandler .php .phtml .php5 .php7
    AddType text/plain .php .phtml .php5 .php7
</Directory>