A vulnerability in the FTP service of Western Digital My Cloud OS 5 devices running firmware versions prior to 5.26.119 allows an attacker to read and write arbitrary files. This could lead to a full NAS compromise and would give remote execution capabilities to the attacker.
Solution:
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.
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.