SignalR security warning : Missing Cross-Frame Scripting Defence - asp.net-mvc

Question

A security scanning app picked up a risk against a signalR link in my asp.net MVC 5 website.
the X-Frame-Options response header is missing, which may allow
Cross-Frame Scripting attacks
Any one can tell me what's this about?
And How to solve it?
ASP.NET SignalR Input Validation Flaw Permits Cross-Site Scripting Attacks
Should not be the problem since I am using SignalR 2.1.x
The request is :
POST ***/signalr/send?transport=serverSentEvents&clientProtocol=1.4&connectionToken=bla**bla** HTTP/1.1
Host: ****
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0.1) Gecko/20100101 Firefox/8.0.1
Accept: text/plain, */*; q=0.01
Accept-Language: en-us,en;q=0.5
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: myhost
Pragma: no-cache
Cache-Control: no-cache
Cookie: authentication token
Content-Length: 113
data=********
The Response is :
HTTP/1.1 200 OK
Cache-Control: no-cache
Pragma: no-cache
Transfer-Encoding: chunked
Content-Type: application/json; charset=UTF-8
Expires: -1
Server: Microsoft-IIS/8.0
X-Content-Type-Options: nosniff
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Some html body

Answer 1

I think this warning can safely be ignored. The X-Frame-Options header is used to prevent clickjacking. SignalR responses don't have any links or any other clickable content.
However, it might be a good idea to set an X-Frame-Options header on every response to be extra safe. You can do this via IIS manager or web.config. If you are not using IIS, you can use OWIN middleware instead.