projectdiscovery/nuclei · error

headless template threads must be at least 1

Error message

headless template threads must be at least 1

What it means

splitSharePath trims slashes off the smb:// URL path and errors when nothing remains: every smb:// URL must name at least host/share. smb://host or smb://host/ leaves no share segment, so parsing aborts before any connection is attempted.

Source

Thrown at lib/config.go:142

	TemplatePayloadConcurrency    int // max concurrent payloads to run for a template (a good default is 25)
	ProbeConcurrency              int // max concurrent http probes to run (a good default is 50)
}

// WithConcurrency sets concurrency options
func WithConcurrency(opts Concurrency) NucleiSDKOptions {
	return func(e *NucleiEngine) error {
		// minimum required is 1
		if opts.TemplateConcurrency <= 0 {
			return errors.New("template threads must be at least 1")
		}
		if opts.HostConcurrency <= 0 {
			return errors.New("host concurrency must be at least 1")
		}
		if opts.HeadlessHostConcurrency <= 0 {
			return errors.New("headless host concurrency must be at least 1")
		}
		if opts.HeadlessTemplateConcurrency <= 0 {
			return errors.New("headless template threads must be at least 1")
		}
		if opts.JavascriptTemplateConcurrency <= 0 {
			return errors.New("js must be at least 1")
		}
		if opts.TemplatePayloadConcurrency <= 0 {
			return errors.New("payload concurrency must be at least 1")
		}
		if opts.ProbeConcurrency <= 0 {
			return errors.New("probe concurrency must be at least 1")
		}
		e.opts.TemplateThreads = opts.TemplateConcurrency
		e.opts.BulkSize = opts.HostConcurrency
		e.opts.HeadlessBulkSize = opts.HeadlessHostConcurrency
		e.opts.HeadlessTemplateThreads = opts.HeadlessTemplateConcurrency
		e.opts.JsConcurrency = opts.JavascriptTemplateConcurrency
		e.opts.PayloadConcurrency = opts.TemplatePayloadConcurrency
		e.opts.ProbeConcurrency = opts.ProbeConcurrency
		return nil

View on GitHub (pinned to 265b3a3dec)

Solutions

1. Add the share name: smb://host/share/file.txt
2. List available shares first and use an exact name

Example fix

# before
smb://fileserver/
# after
smb://fileserver/public/report.pdf

import (
    "net/url"
    "strings"
)

func smbURLHasShare(raw string) bool {
    u, err := url.Parse(raw)
    if err != nil {
        return false
    }
    return strings.Trim(u.Path, "/") != ""
}

When it happens

Trigger: smb://host or smb://host/ passed as a file target - the path component is empty after trimming slashes.

Common situations: Probing host reachability with a bare smb://host URL; the share name typo'd into the host part.

Related errors

• host concurrency must be at least 1
• share path contains NUL
• share name must not contain path separators: %q
• no templates provided for scan
• no input provider found

AI-assisted analysis of projectdiscovery/nuclei@265b3a3dec (2026-08-15). Data as JSON: /api/errors/656863c447ff010c. Report an issue: GitHub.