{"record":{"id":"253291c0b8456657","repo":"sqlmapproject/sqlmap","slug":"malformed-backend-message-s","errorCode":null,"errorMessage":"malformed backend message: %s","messagePattern":"malformed backend message: (.+?)","errorType":"exception","errorClass":"InterfaceError","httpStatus":null,"severity":"error","filePath":"extra/dbwire/postgres.py","lineNumber":221,"sourceCode":"                                try:\n                                    row.append(raw.decode(\"utf-8\"))\n                                except UnicodeDecodeError:\n                                    row.append(raw)  # non-UTF-8 (e.g. a SQL_ASCII db): keep bytes (hex-encoded), not lossy U+FFFD\n                    rows.append(tuple(row))\n                elif mtype == b\"C\":  # CommandComplete (\"SELECT 3\", \"INSERT 0 1\", ...)\n                    tag = payload[:-1].decode(\"utf-8\", \"replace\").split()\n                    if tag and tag[-1].isdigit():\n                        rowcount = int(tag[-1])\n                elif mtype == b\"G\":  # CopyInResponse - server now waits for client CopyData; refuse to avoid a deadlock\n                    _send(self._sock, b\"f\", b\"COPY FROM STDIN is not supported\\x00\")  # CopyFail\n                elif mtype == b\"E\":  # ErrorResponse\n                    error = _error_message(payload)\n                elif mtype == b\"Z\":  # ReadyForQuery (end of response); payload byte = transaction status\n                    self._txn_status = payload[:1] or b\"I\"\n                    break\n                # ParameterStatus(S)/NoticeResponse(N)/EmptyQueryResponse(I)/CopyData(d)/CopyDone(c)/... ignored\n            except (struct.error, IndexError, ValueError) as ex:\n                raise InterfaceError(\"malformed backend message: %s\" % ex)\n        if error is not None:\n            _raise_server_error(*error)\n        return description, rows, 0, rowcount\n\ndef _authenticate(sock, user, password):\n    client_nonce = cfirst_bare = salted = auth_message = None\n    while True:\n        mtype, payload = _read_message(sock)\n        if mtype in (b\"N\", b\"S\"):  # NoticeResponse / ParameterStatus may legally precede AuthenticationOk\n            continue\n        if mtype == b\"E\":\n            _raise_server_error_as_operational(payload)\n        if mtype != b\"R\":\n            raise InterfaceError(\"unexpected message %r during authentication\" % mtype)\n        (code,) = struct.unpack(\"!I\", payload[:4])\n        if code == 0:  # AuthenticationOk (also the trust case)\n            return\n        elif code == 3:  # cleartext password","sourceCodeStart":203,"sourceCodeEnd":239,"githubUrl":"https://github.com/sqlmapproject/sqlmap/blob/0a35b20e3953d341be6c7ac75ccb0b3362540c8d/extra/dbwire/postgres.py#L203-L239","documentation":"Error \"malformed backend message: %s\" thrown in sqlmapproject/sqlmap.","triggerScenarios":"Thrown at extra/dbwire/postgres.py:221 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"0a35b20e3953d341be6c7ac75ccb0b3362540c8d","analyzedAt":"2026-08-26T23:02:52.002Z","schemaVersion":2},"datasetVersion":"2026-08-27T03:17:27.898Z"}