shadow1ng/fscan · error

fscan: target host or URL is required

Error message

fscan: target host or URL is required

What it means

Per-target validation in pkg/fscan validateConfig: a Target entry has both an empty Host and an empty URL (whitespace-only counts as empty), so the target carries no address to connect to. It fires only after target-count and plugin checks passed, catching malformed Target structs built by the caller.

Source

Thrown at pkg/fscan/scanner.go:347

	return core.RunScan(ctx, info, session)
}

func validateConfig(config Config, targets []Target) error {
	if len(targets) == 0 {
		return fmt.Errorf("fscan: at least one target is required")
	}
	for _, name := range normalizePlugins(config.Plugins) {
		if !plugins.Exists(name) {
			return fmt.Errorf("fscan: plugin %q not found", name)
		}
		if !config.AllowUnsafePlugins && !IsSafePlugin(name) {
			return fmt.Errorf("fscan: plugin %q is not enabled for embedded safe mode", name)
		}
	}
	for _, target := range targets {
		if strings.TrimSpace(target.Host) == "" && strings.TrimSpace(target.URL) == "" {
			return fmt.Errorf("fscan: target host or URL is required")
		}
		if strings.TrimSpace(target.Host) != "" && strings.TrimSpace(target.URL) != "" {
			return fmt.Errorf("fscan: target cannot set both Host and URL")
		}
		for _, port := range target.Ports {
			if port < 1 || port > 65535 {
				return fmt.Errorf("fscan: invalid port %d", port)
			}
		}
	}
	for _, port := range config.Ports {
		if port < 1 || port > 65535 {
			return fmt.Errorf("fscan: invalid port %d", port)
		}
	}
	return nil
}

View on GitHub (pinned to 95cc12e753)

Solutions

1. Populate either Target.Host or Target.URL
2. Filter empty targets out of the list before scanning
3. Fix target-source parsing that produced blank entries

When it happens

Trigger: Thrown at pkg/fscan/scanner.go:347 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06). Data as JSON: /api/errors/242ff121ea7d6210. Report an issue: GitHub.