Improper Input Validation
administrator/index.php in the installer component (com_installer) in Joomla! 1.5 Beta1, Beta2, and RC1 allows remote authenticated administrators to upload arbitrary files to tmp/ via the "Upload Package File" functionality, which is accessible when com_installer is the value of the option parameter.
CWE-20 - 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.