[BUG] Nuclei can't set headers in DAST fuzzing templates

[zerokeeper]

Is there an existing issue for this?

• I have searched the existing issues.

Current Behavior

can't set headers in DAST fuzzing templates.

Expected Behavior

can set custom headers in DAST fuzzing templates.

Steps To Reproduce

nuclei -dast -t simple-fuzzing-test.yaml -u http://127.0.0.1/?id=1 -debug-req

id: simple-fuzzing-test

info:
  name: Simple Fuzzing Test
  author: test
  severity: high

http:
  - method: GET
    path:
      - "{{BaseURL}}/test?id=1"
    headers:
      test: abc
      User-Agent: ua
    fuzzing:
      - part: query
        type: replace
        keys:
          - id
        fuzz:
          - 1
          - 2
    matchers:
      - type: status
        status:
          - 200

Relevant log output

____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.3.8

		projectdiscovery.io

[WRN] The concurrency value is higher than max-host-error
[INF] Adjusting max-host-error to the concurrency value: 50
[INF] Current nuclei version: v3.3.8 (outdated)
[INF] Current nuclei-templates version: v9.6.8 (outdated)
[WRN] Scan results upload to cloud is disabled.
[INF] New templates added in latest release: 11
[INF] Templates loaded for current scan: 1
[WRN] Loading 1 unsigned templates for scan. Use with caution.
[INF] Targets loaded for current scan: 1
[INF] [simple-fuzzing-test] Dumped HTTP request for http://127.0.0.1/?id=1

GET /?id=1 HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11) AppleWebKit/616.17 (KHTML, like Gecko) Version/17.3.75 Safari/616.17
Accept-Encoding: gzip

[INF] [simple-fuzzing-test] Dumped HTTP request for http://127.0.0.1/?id=2

GET /?id=2 HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11) AppleWebKit/616.17 (KHTML, like Gecko) Version/17.3.75 Safari/616.17
Accept-Encoding: gzip

[INF] No results found. Better luck next time!
[0:00:00] | Templates: 1 | Hosts: 1 | RPS: 7 | Matched: 0 | Errors: 2 | Requests: 2/1 (200%)

Environment

- OS: mac os
- Nuclei: 3.3.8

Anything else?

No response

[ehsandeep]

Test template used for testing:

id: simple-fuzzing-test

info:
  name: Simple Fuzzing Test
  author: test
  severity: high

http:
  - pre-condition:
      - type: dsl
        dsl:
          - 'method == "GET"'

    headers:
      test: abc
      User-Agent: ua

    fuzzing:
      - part: query
        type: replace
        keys:
          - id

        fuzz:
          - 1
          - 2

    matchers:
      - type: status
        status:
          - 200