Unrestricted Upload of File with Dangerous Type
In JFinal cos before 2019.8 as used in JFinal 4.4, there is a vulnerability that can bypass the isSafeFile() function: one can upload any type of file. For example, a .jsp file may be stored and almost immediately deleted, but this deletion step does not occur for certain exceptions.
CWE-434 - Unrestricted Upload of File with dangerous type
'Unrestricted file upload with dangerous type' attacks involve an attacker uploading or transferring files of dangerous types to the server. The severity of such an attack depends upon the execution mechanism and the storage location of the uploaded file. Thus, it may range from simple defacement to arbitrary file execution, and complete system takeover.