The Image Manager in MOStlyCE before 2.4, as used in Mambo 4.6.3 and earlier, allows remote attackers to rename arbitrary files and cause a denial of service via modified file[NewFile][name], file[NewFile][tmp_name], and file[NewFile][size] parameters in a FileUpload command, which are used to modify equivalent variables in $_FILES that are accessed when the is_uploaded_file check fails.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.