CVE-2021-23814: Improper Control of Generation of Code

This affects versions of the package unisharp/laravel-filemanager before 2.6.2. The upload() function does not sufficiently validate the file type when uploading. An attacker may be able to reproduce the following steps: 1. Install a package with a web Laravel application. 2. Navigate to the Upload window 3. Upload an image file, then capture the request 4. Edit the request contents with a malicious file (webshell) 5. Enter the path of file uploaded on URL - Remote Code Execution **Note:** Prevention for bad extensions can be done by using a whitelist in the config file(lfm.php). Corresponding document can be found in [here](https://unisharp.github.io/laravel-filemanager/configfolder-categories).