From 7748411200fb15e71fcacd6a148f14dc91a3ae61 Mon Sep 17 00:00:00 2001
From: anant <170962632+antcybersec@users.noreply.github.com>
Date: Thu, 5 Nov 2026 09:59:47 +0530
Subject: [PATCH] fix(cmd): keep "#" in -H header values

Signed-off-by: anant <170962632+antcybersec@users.noreply.github.com>
---
 cmd/nuclei/header_test.go | 57 +++++++++++++++++++++++++++++++++++++++
 cmd/nuclei/main.go        | 18 ++++++++++++-
 2 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 cmd/nuclei/header_test.go

diff --git a/cmd/nuclei/header_test.go b/cmd/nuclei/header_test.go
new file mode 100644
index 000000000..ba73b9fd5
--- /dev/null
+++ b/cmd/nuclei/header_test.go
@@ -0,0 +1,57 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/projectdiscovery/gologger"
+	"github.com/projectdiscovery/nuclei/v3/pkg/types"
+	"github.com/stretchr/testify/require"
+)
+
+const headerChildEnv = "NUCLEI_HEADER_CHILD_ARGS"
+
+// -H values can contain "#", on the command line, in a header file and in the
+// config file, while lines of a header file that start with "#" are skipped as
+// comments.
+func TestHeaderValuesKeepHash(t *testing.T) {
+	if args := os.Getenv(headerChildEnv); args != "" {
+		options = &types.Options{Logger: gologger.DefaultLogger}
+		os.Args = append([]string{os.Args[0]}, strings.Split(args, "\n")...)
+		readConfig()
+		fmt.Printf("headers=%s\n", strings.Join(options.CustomHeaders, "|"))
+		os.Exit(0)
+	}
+
+	root := t.TempDir()
+	headerFile := filepath.Join(root, "headers.txt")
+	require.NoError(t, os.WriteFile(headerFile, []byte("# auth headers\nX-Token: abc#def\nReferer: https://app.example.com/#/dashboard\n"), 0o600))
+	configFile := filepath.Join(root, "config.yaml")
+	require.NoError(t, os.WriteFile(configFile, []byte("header:\n  - \"X-Config: cfg#value\"\n"), 0o600))
+
+	tests := []struct {
+		name string
+		args []string
+		want string
+	}{
+		{"cli and header file", []string{"-H", "Cookie: sid=1; color=#ff0000", "-H", headerFile}, "Cookie: sid=1; color=#ff0000|X-Token: abc#def|Referer: https://app.example.com/#/dashboard"},
+		{"config file", []string{"-config", configFile}, "X-Config: cfg#value"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tempRoot := filepath.Join(t.TempDir(), "tmp")
+			require.NoError(t, os.Mkdir(tempRoot, 0o700))
+
+			args := append(tt.args, "-disable-update-check")
+			cmd := exec.Command(os.Args[0], "-test.run=^TestHeaderValuesKeepHash$", "-test.count=1")
+			cmd.Env = isolatedNucleiStorageEnv(root, tempRoot, headerChildEnv+"="+strings.Join(args, "\n"))
+			output, err := cmd.CombinedOutput()
+			require.NoError(t, err, string(output))
+			require.Contains(t, string(output), "headers="+tt.want+"\n")
+		})
+	}
+}
diff --git a/cmd/nuclei/main.go b/cmd/nuclei/main.go
index 39d4d3a26..234442e95 100644
--- a/cmd/nuclei/main.go
+++ b/cmd/nuclei/main.go
@@ -55,6 +55,17 @@ var (
 	inlineSecretsTempMu  sync.Mutex
 )
 
+// normalizeHeaderValue trims a -H value and drops it when the whole line is a
+// "#" comment. The goflags default strips inline comments, which cut values
+// such as "Cookie: color=#fff" at the "#".
+func normalizeHeaderValue(s string) string {
+	s = strings.TrimSpace(s)
+	if strings.HasPrefix(s, "#") {
+		return ""
+	}
+	return s
+}
+
 func main() {
 	options.Logger = gologger.DefaultLogger
 
@@ -255,6 +266,11 @@ func readConfig() *goflags.FlagSet {
 	var pdcpAuth string
 	var fuzzFlag bool
 
+	// FileStringSliceOptions as set up by runner.ConfigureOptions, but keeping
+	// "#" inside -H values
+	headerSliceOptions := goflags.FileStringSliceOptions
+	headerSliceOptions.Normalize = normalizeHeaderValue
+
 	flagSet := goflags.NewFlagSet()
 	flagSet.CaseSensitive = true
 	flagSet.SetDescription(`Nuclei is a fast, template based vulnerability scanner focusing
@@ -367,7 +383,7 @@ on extensive configurability, massive extensibility and ease of use.`)
 		flagSet.IntVarP(&options.MaxRedirects, "max-redirects", "mr", 10, "max number of redirects to follow for http templates"),
 		flagSet.BoolVarP(&options.DisableRedirects, "disable-redirects", "dr", false, "disable redirects for http templates"),
 		flagSet.StringVarP(&options.ReportingConfig, "report-config", "rc", "", "nuclei reporting module configuration file"), // TODO merge into the config file or rename to issue-tracking
-		flagSet.StringSliceVarP(&options.CustomHeaders, "header", "H", nil, "custom header/cookie to include in all http request in header:value format (cli, file)", goflags.FileStringSliceOptions),
+		flagSet.StringSliceVarP(&options.CustomHeaders, "header", "H", nil, "custom header/cookie to include in all http request in header:value format (cli, file)", headerSliceOptions),
 		flagSet.RuntimeMapVarP(&options.Vars, "var", "V", nil, "custom vars in key=value format"),
 		flagSet.StringVarP(&options.ResolversFile, "resolvers", "r", "", "file containing resolver list for nuclei"),
 		flagSet.BoolVarP(&options.SystemResolvers, "system-resolvers", "sr", false, "use system DNS resolving as error fallback"),