Duplicate Connection header being added to requests if the value of the header is other than closed

[parthmalhotra]

A duplicate Connection header gets added to the request if it is anything other than Connection: close

i.e If a template already has Connection: keep-alive, nuclei is automatically adding a Duplicate Connection header to the request.

nuclei -turl https://cloud.projectdiscovery.io/@parth/gr7HoNWiYApUmZY3CxMTZ6 -u https://www.zomato.com/ -debug -proxy http://127.0.0.1:8080

Template :

id: zomato-homepage-status-check

info:
  name: Zomato Homepage Status Check
  author: ProjectDiscoveryAI
  severity: info
  description: |
    This template checks the status code of the Zomato homepage to ensure it returns a 200 status code.

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: www.zomato.com
        Accept-Encoding: gzip, deflate, br
        Accept: */*
        Accept-Language: en-US;q=0.9,en;q=0.8
        User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.6668.71 Safari/537.36
        Connection: keep-alive
        Referer: https://zomato.com/

    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200

Request (Going through Proxy) :

GET / HTTP/1.1
Host: www.zomato.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.6668.71 Safari/537.36
Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US;q=0.9,en;q=0.8
Connection: keep-alive
Referer: https://zomato.com/
Connection: keep-alive