    def request(self, method, request_uri, headers, content):
        """Modify the request headers"""
        keys = _get_end2end_headers(headers)
        keylist = "".join(["%s " % k for k in keys])
        headers_val = "".join([headers[k] for k in keys])
        created = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
        cnonce = _cnonce()
        request_digest = "%s:%s:%s:%s:%s" % (
            method,
            request_uri,
            cnonce,
            self.challenge["snonce"],
            headers_val,
        )
        request_digest = (
            hmac.new(self.key, request_digest, self.hashmod).hexdigest().lower()
        )
        headers["authorization"] = (
            'HMACDigest username="%s", realm="%s", snonce="%s",'
            ' cnonce="%s", uri="%s", created="%s", '
            'response="%s", headers="%s"'
        ) % (
            self.credentials[0],
            self.challenge["realm"],
            self.challenge["snonce"],
            cnonce,
            request_uri,
            created,
            request_digest,
            keylist,
        )
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.