ImpressCMS v1.4.4 - Unrestricted File Upload Vulnerability

# Exploit Title: ImpressCMS v1.4.4 - Unrestricted File Upload
# Exploit Author: Ünsal Furkan Harani (Zemarkhos)
# Vendor Homepage: https://www.impresscms.org/
# Software Link: https://github.com/ImpressCMS/impresscms
# Version: v1.4.4

# Description:
Between lines 152 and 162, we see the function "extensionsToBeSanitized".Since the blacklist method is weak, it is familiar that the file can be uploaded in the extensions mentioned below.

.php2, .php6, .php7, .phps, .pht, .pgif, .shtml, .htaccess, .phar, .inc

Impresscms/core/File/MediaUploader.php Between lines 152 and 162:
private $extensionsToBeSanitized = array('php','phtml','phtm','php3','php4','cgi','pl','asp','php5');