cmseasy V7.7.5_20211012 is affected by an arbitrary file write vulnerability. Through this vulnerability, a PHP script file is written to the website server, and accessing this file can lead to a code execution vulnerability.
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.