Pulse Secure version 9.115 and below may be susceptible to client-side http request smuggling, When the application receives a POST request, it ignores the request's Content-Length header and leaves the POST body on the TCP/TLS socket. This body ends up prefixing the next HTTP request sent down that connection, this means when someone loads website attacker may be able to make browser issue a POST to the application, enabling XSS.
CWE-444, CWE-444