epi052/feroxbuster · error

Empty header name provided

Error message

Empty header name provided

What it means

split_header requires a non-empty header name before the first `:`. If the input starts with `:` (or the name is only whitespace after trimming), no header name exists and the function throws. Unlike the multiple-colon case, the value may still contain colons — only the name may not be empty.

Solutions

1. Add the missing header name before the colon (e.g. `Authorization: Bearer xyz`)
2. Check templated request files for header-name variables that expand to empty strings
3. Validate each header entry matches `Name: value` before passing it to the parser

Example fix

// before
xatu --header ": application/json"
// after
xatu --header "Content-Type: application/json"

if !h.trim().is_empty() && !h.trim_start().starts_with(':') { /* safe to parse */ }

match split_header(entry) {
    Ok((name, value)) => insert_header(name, value),
    Err(e) => eprintln!("invalid header entry '{entry}': {e}"),
}

When it happens

Trigger: Calling split_header(":value") or split_header(" :value") — everything before the first `:` is empty after trim.

Common situations: Typos where the header name was deleted (`-H ": Bearer xyz"`), templated request files where the header-name variable was empty, or hand-edited header lines missing `Authorization:` etc.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Empty header provided
• Empty query string provided
• Empty key in query string
• Empty --request-file file provided
• Invalid request: Missing head/body separator

AI-assisted analysis of epi052/feroxbuster@1f595dab5c (2026-09-13). Data as JSON: /api/errors/dbf92764a518e0de. Report an issue: GitHub.

Appendix: source

Thrown at src/config/utils.rs:316

///   or an error if the input is invalid.
///
/// # Errors
///
/// This function will return an error if:
/// * The input string is empty.
/// * The key part of the header string is empty (i.e., if the string starts with `":"`).
pub fn split_header(header: &str) -> Result<(String, String)> {
    if header.is_empty() {
        bail!("Empty header provided");
    }

    let mut split_val = header.split(':');

    // explicitly take first split value as header's name
    let name = split_val.next().unwrap().trim().to_string();

    if name.is_empty() {
        bail!("Empty header name provided");
    }

    // all other items in the iterator returned by split, when combined with the
    // original split deliminator (:), make up the header's final value
    let value = split_val.collect::<Vec<&str>>().join(":");

    if value.starts_with(' ') && !value.starts_with("  ") {
        // first character is a space and the second character isn't
        // we can trim the leading space
        let trimmed = value.trim_start();
        Ok((name, trimmed.to_string()))
    } else {
        Ok((name, value))
    }
}

/// Combines two `Cookie` header strings into a single, unified `Cookie` header string.
///

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