sqlmapproject/sqlmap · error · SqlmapDataException

Esperanto could not establish a reliable extraction oracle…

Error message

Esperanto could not establish a reliable extraction oracle on this target (%s)

What it means

Top-level engine failure surfaced by the handler: Esperanto's discover() could not establish any reliable boolean-blind extraction oracle on the target (sanity, substring or length discovery all failed). The handler wraps it so the scan can fall back to whatever other technique is available.

Solutions

1. Fall back to the default technique selection for the target
2. Verify the injection point and true/false page discrimination manually
3. Retry with more retries/quorum or a different parameter

When it happens

Trigger: Thrown at extra/esperanto/handler.py:81 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/7b4bfb3e3db6832e. Report an issue: GitHub.

Appendix: source

Thrown at extra/esperanto/handler.py:81

                # boolean-blind technique: no marker, no concatenation, whole-page true/false,
                # works everywhere. only fall back to whatever-technique-is-available if the
                # target has no usable boolean-blind vector. _ask decides what an undecidable
                # probe MEANS by context (skip a candidate rung vs degrade a data read loudly).
                esp = Esperanto(_blindOracle, retries=2)
                logger.info("Esperanto is discovering the back-end SQL dialect (agnostic mode, boolean-blind)")
                try:
                    esp.discover()
                except RuntimeError:
                    # no usable boolean-blind vector on this target - retry with any technique
                    # sqlmap detected (UNION/error/time); may hit the CONCAT limitation above
                    esp = Esperanto(lambda condition: checkBooleanExpression(condition), retries=2)
                    logger.info("Esperanto retrying discovery via any available inference technique")
                    try:
                        esp.discover()
                    except RuntimeError as ex:
                        # genuinely unusable (unstable target, or no substring/pattern
                        # primitive) - stop cleanly instead of surfacing an internal traceback
                        raise SqlmapDataException("Esperanto could not establish a reliable extraction oracle on this target (%s)" % ex)
                logger.info("Esperanto dialect verdict: %s" % (esp.identify().get("product") or "unknown"))
                esp._progress = lambda value: logger.info("retrieved: %s" % _sanitize(value))  # live feedback (sanitized)
                self._esp = esp
                self._notesLogged = 0
                self._flushNotes()                      # discovery-time notes
            return self._esp

        def _flushNotes(self):
            # surface degradation notes LOUDLY as they accrue. Enumeration/dump append notes
            # AFTER discovery, so logging once would hide every runtime degradation (incomplete
            # listing, truncation, blocked paging) - flush the NEW ones after each operation.
            notes = self._esp.dialect.notes if self._esp else []
            for note in notes[self._notesLogged:]:
                logger.warning("Esperanto: %s" % note)
            self._notesLogged = len(notes)

        def _scopeDb(self):
            # the database to scope table/column lookups to: -D if given, else the

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