The file upload plugin in Adminer and AdminerEvo allows an attacker to upload a file with a table name of “..” to the root of the Adminer directory. The attacker can effectively guess the name of the uploaded file and execute it. Adminer is no longer supported, but this issue was fixed in AdminerEvo version 4.8.3.
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.
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.