tmp_path does not exists, should be tmp_name
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 05511b5..fe5907a 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -1055,7 +1055,7 @@
if (DIRECTORY_SEPARATOR !== '\\' && function_exists('exec'))
{
$output = array();
- @exec('file --brief --mime-type ' . escapeshellarg($file['tmp_path']), $output, $return_code);
+ @exec('file --brief --mime-type ' . escapeshellarg($file['tmp_name']), $output, $return_code);
if ($return_code === 0 && strlen($output[0]) > 0) // A return status code != 0 would mean failed execution
{
$this->file_type = rtrim($output[0]);