When we get into the website :  
http://10xm9f04zpaze7u3p2at5ju70.ctf.p0wnhub.com:5000/

we can see that there is a simple form to get topics of the event so i tried
to submit the form with that request:  
```  
POST /notifications HTTP/1.1  
Host: 10xm9f04zpaze7u3p2at5ju70.ctf.p0wnhub.com:5000  
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:75.0) Gecko/20100101
Firefox/75.0  
Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8  
Accept-Language: fr,fr-FR;q=0.8,en-US;q=0.5,en;q=0.3  
Accept-Encoding: gzip, deflate  
Content-Type: multipart/form-data;
boundary=---------------------------16653180638431225724194145577  
Content-Length: 175  
Origin: http://10xm9f04zpaze7u3p2at5ju70.ctf.p0wnhub.com:5000  
Connection: close  
Referer: http://10xm9f04zpaze7u3p2at5ju70.ctf.p0wnhub.com:5000/  
Upgrade-Insecure-Requests: 1

\-----------------------------16653180638431225724194145577  
Content-Disposition: form-data; name="topic"

CTF  
\-----------------------------16653180638431225724194145577--  
```  
and as a normal hacker i tried to make some parameter pollution so i decided
to change `"topic" and i writed "topics"`.  
Then i got a differend response!

I've got the python flask debugger page and while scrolling to see Exceptions
I've found the flag !

and Bingoo : `HZVIII{K4fka_1ns3cure_t0p1C}`