Bug issue with XXE upload

[dugdug36]

Hello,

When i try to make XXE via upload with for example :

Client side:

]>

John
Doe
Doe
&xxe;

Server side:
Error on request:
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 323, in run_wsgi
execute(self.server.app)
File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 315, in execute
write(data)
File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 273, in write
self.send_response(code, msg)
File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 388, in send_response
self.wfile.write(hdr.encode("ascii"))
IOError: [Errno 32] Broken pipe

In addition can you write write-up to know how to exploit every part of this flask ?.
@lokori