epi052/feroxbuster · error

Invalid request: Could not parse target URL

Error message

Invalid request: Could not parse target URL {}

What it means

Thrown by parse_request_file when the assembled target URL (from Host header + URI or an absolute request URI) cannot be parsed by parse_url_with_raw_path. The URL exists syntactically but is not a valid parseable URL, so the scan scope cannot be established.

Solutions

1. Inspect the parsed target (the URL is printed in the error) and fix the Host header or absolute URI in the request file
2. Remove scheme prefixes from the Host header — it should be 'Host: example.com', not 'Host: https://example.com'
3. URL-encode invalid characters in the path/URI (spaces, quotes, unicode)
4. Test the URL with a parser (e.g. python -c "import urlparse...") before feeding it to the tool

Example fix

// before
"GET / HTTP/1.1\nHost: https://example.com/path"
// after
"GET /path HTTP/1.1\nHost: example.com"

fn host_header_is_clean(raw: &str) -> Result<(), String> {
    for line in raw.lines() {
        if let Some(v) = line.strip_prefix("Host:") {
            let v = v.trim();
            if v.contains(' ') || v.starts_with("http") {
                return Err(format!("suspicious Host header value: {v}"));
            }
        }
    }
    Ok(())
}

When it happens

Trigger: target_url built from a malformed Host header (e.g. 'Host: http://weird host' with spaces) or a bogus absolute URI like 'GET htt[p://x' — the URL string is non-empty but unparseable.

Common situations: Copy-pasted Host values including protocol or trailing slashes; typos in the scheme of an absolute request URI; control characters or non-ASCII in Host captured from a corrupted request.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• Invalid request: Missing Host header and request line URI…
• Invalid request: Empty method
• Invalid request: Missing request line URI
• Invalid request: Empty request line URI
• JSON has no tag_name

AI-assisted analysis of epi052/feroxbuster@1f595dab5c (2026-09-13). Data as JSON: /api/errors/db472085cf23a9d7. Report an issue: GitHub.

Appendix: source

Thrown at src/config/utils.rs:600

        config.scope.push(url);
    } else {
        // uri in request line is not a valid URL, so it's most likely a path/relative url
        // we need to combine it with the host header
        for (key, value) in &config.headers {
            if key.to_lowercase() == "host" {
                config.target_url = format!("{}://{value}{uri}", config.protocol);
                break;
            }
        }

        if config.target_url.is_empty() {
            bail!("Invalid request: Missing Host header and request line URI isn't a full URL");
        }

        if let Ok(url) = parse_url_with_raw_path(&config.target_url) {
            config.scope.push(url);
        } else {
            bail!(
                "Invalid request: Could not parse target URL {}",
                config.target_url
            );
        }

        // need to parse queries from the uri, if any are present
        let mut uri_parts = uri.splitn(2, '?');

        // skip the path
        uri_parts.next();

        if let Some(queries) = uri_parts.next() {
            let query_parts = queries.split("&");

            query_parts.into_iter().for_each(|query| {
                let Ok((name, value)) = split_query(query) else {
                    return;
                };

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