The Simple Backup plugin for WordPress is vulnerable to Arbitrary File Download in versions up to, and including, 2.7.10. via the download_backup_file function. This is due to a lack of capability checks and file type validation. This makes it possible for attackers to download sensitive files such as the wp-config.php file from the affected site.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.