CVE-2025-56399: Laravel File Manager RCE Vulnerability

CVE-2025-56399 Overview

CVE-2025-56399 is a remote code execution vulnerability in the alexusmai laravel-file-manager package, affecting version 3.3.1 and earlier. An authenticated attacker can upload a file with a .png extension that contains PHP code through the file manager interface. Although client-side validation reports the upload as failed, the server still writes the file to disk. The attacker then invokes the rename API to change the extension to .php and triggers code execution by requesting the file via a public URL. The flaw is classified as Improper Control of Generation of Code [CWE-94].

Critical Impact
An authenticated user can achieve full remote code execution on the host running the Laravel application, compromising confidentiality, integrity, and availability.

Affected Products

alexusmai laravel-file-manager 3.3.1
alexusmai laravel-file-manager versions prior to 3.3.1
Laravel applications integrating the vulnerable package

Discovery Timeline

2025-10-28 - CVE-2025-56399 published to NVD
2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-56399

Vulnerability Analysis

The vulnerability allows an authenticated attacker to bypass file type restrictions and place executable PHP code into a web-accessible directory. The file manager performs extension validation client-side, but the server persists the uploaded content regardless of the validation outcome. The attacker leverages the package's own rename endpoint to change the file extension from .png to .php. The web server then interprets the file as PHP source code on the next HTTP request, executing the embedded payload under the privileges of the PHP runtime.

Root Cause

The root cause is a combination of weak server-side validation during upload and an unrestricted rename operation. The package trusts client-side validation, accepts the file content, and exposes a rename API that does not enforce an allowlist of safe target extensions. Because the upload directory is reachable from a public URL, the renamed file becomes directly executable through the web server.

Attack Vector

Exploitation requires authenticated access to the file manager interface but no elevated privileges. The attacker submits a crafted file containing PHP code with a .png extension, observes that the client reports the upload as rejected, and confirms that the file is present on the server. The attacker then calls the rename endpoint to switch the extension to .php and issues an HTTP GET request to the resulting URL to execute the payload. A proof-of-concept is published in the GitHub PoC for CVE-2025-56399 repository. Additional product details are available on the Laravel File Manager Resource site.

Detection Methods for CVE-2025-56399

Indicators of Compromise

Files written to file manager upload directories with image extensions whose binary content begins with <?php or contains PHP tags.
Rename API requests that change file extensions from image formats (.png, .jpg, .gif) to executable formats (.php, .phtml, .php5).
Outbound HTTP requests from the web server process to unfamiliar hosts shortly after a file rename event.
Unexpected PHP processes spawning shell utilities such as sh, bash, curl, or wget from within the application's storage path.

Detection Strategies

Inspect web server access logs for sequential upload and rename calls to laravel-file-manager endpoints originating from the same authenticated session.
Scan upload directories for files whose declared extension and MIME type do not match the underlying content using utilities such as file or YARA rules targeting PHP tags.
Alert on any PHP file written under directories normally restricted to user-uploaded media.

Monitoring Recommendations

Enable file integrity monitoring on the Laravel storage/ and public/ paths used by the file manager.
Forward web server, PHP-FPM, and application logs to a central SIEM and correlate authentication, upload, and rename events.
Monitor process execution telemetry on the application host for PHP interpreter invocations that spawn command-line tools.

How to Mitigate CVE-2025-56399

Immediate Actions Required

Restrict access to the file manager interface to trusted administrative accounts and enforce multi-factor authentication.
Disable the rename endpoint or remove the file manager package until a patched release is deployed.
Configure the web server to refuse execution of PHP files within user upload directories.

Patch Information

No fixed version has been published in the available CVE references at the time of writing. Track the Laravel File Manager Resource site and the package repository for an upstream release that addresses both the upload validation gap and the unrestricted rename behavior.

Workarounds

Add server-side validation that inspects file content (magic bytes and MIME) and rejects any file containing PHP tags regardless of extension.
Maintain a strict allowlist of permitted target extensions for the rename API and reject .php, .phtml, .phar, and similar executable suffixes.
Serve user-uploaded files from a separate domain or storage backend configured to return content with Content-Disposition: attachment and without PHP handling.
Apply web server rules that deny execution within upload directories, for example using an Apache <Directory> block with php_flag engine off or an Nginx location block that does not pass requests to PHP-FPM.

bash

# Nginx configuration example: disable PHP execution in uploads
location ^~ /storage/files/ {
    default_type application/octet-stream;
    add_header Content-Disposition "attachment";
    location ~ \.php$ { return 403; }
}