sqlmapproject/sqlmap · error · SqlmapSyntaxException

invalid header value: %s. Valid header format is 'name:value

Error message

invalid header value: %s. Valid header format is 'name:value'

What it means

Error "invalid header value: %s. Valid header format is 'name:value'" thrown in sqlmapproject/sqlmap.

Source

Thrown at lib/core/option.py:1580

            conf.headers = conf.headers.replace("\\r\\n", "\\n").split("\\n")
        else:
            conf.headers = conf.headers.replace("\r\n", "\n").split("\n")

        for headerValue in conf.headers:
            if not headerValue.strip():
                continue

            if headerValue.startswith('@'):
                checkFile(headerValue[1:])
                kb.headersFile = headerValue[1:]
            elif headerValue.count(':') >= 1:
                header, value = (_.lstrip() for _ in headerValue.split(":", 1))

                if header and value:
                    conf.httpHeaders.append((header, value))
            else:
                errMsg = "invalid header value: %s. Valid header format is 'name:value'" % repr(headerValue).lstrip('u')
                raise SqlmapSyntaxException(errMsg)

    elif not conf.requestFile and len(conf.httpHeaders or []) < 2:
        if conf.encoding:
            conf.httpHeaders.append((HTTP_HEADER.ACCEPT_CHARSET, "%s;q=0.7,*;q=0.1" % conf.encoding))

        # Invalidating any caching mechanism in between
        # Reference: http://stackoverflow.com/a/1383359
        conf.httpHeaders.append((HTTP_HEADER.CACHE_CONTROL, "no-cache"))

def _setHTTPUserAgent():
    """
    Set the HTTP User-Agent header.
    Depending on the user options it can be:

        * The default sqlmap string
        * A default value read as user option
        * A random value read from a list of User-Agent headers from a
          file choosed as user option

View on GitHub (pinned to 0a35b20e39)

When it happens

Trigger: Thrown at lib/core/option.py:1580 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sqlmapproject/sqlmap@0a35b20e39 (2026-08-26). Data as JSON: /api/errors/39e2d8d8e8deb02b. Report an issue: GitHub.