I tried to upload a pdf file using the media manager and I did not succeed. I sent the file and I did not receive any warning. The file simply do not upload. I noticed that the error depends on the pdf file uploaded, and it occurs due to the method isSafeFile() (class JFilterInput - libraries/joomla/filter/input.php), called within the method get() of the class JInputFiles (libraries/joomla/input/files.php, line 83).

The task upload(), from the media manager backend controller file.php, calls the method JInputFiles::get() through an object on the line 45 ($this->input->files->get).

Why it occurs? It occurs due to the forbidden extensions scan inside file contents, within the JFilterInput::isSafeFile(), from the line 459. In my case, when I saw the variable $data output (declared on line 467) from my pdf file, I found the string ".py" inside the pdf file code, one of the extensions verified by default, inside file contents. Important: the string was not inside the pdf file text.

I understood the importance of the method JFilterInput::isSafeFile(), but the search of simple extensions inside file content, being confused with the pdf file code, can cause problems that most users will not identify the reason.