sqlmapproject/sqlmap · error · InterfaceError

backend message too large (%d bytes)

Error message

backend message too large (%d bytes)

What it means

Error "backend message too large (%d bytes)" thrown in sqlmapproject/sqlmap.

Source

Thrown at extra/dbwire/monetdb.py:43

from extra.dbwire import connection_lost
from extra.dbwire import handshake_done
from extra.dbwire import keepalive
from extra.dbwire import recvn
from extra.dbwire import ProgrammingError

_MAX_BLOCK = 0xffff >> 1
_MAX_MESSAGE_LENGTH = 0x40000000  # cap on a (re-assembled) response, to bound a hostile/corrupt stream

def _getblock(sock):
    # the block length is a 15-bit field, so bounding IT is pointless - a peer that never sets the last-flag
    # simply streams blocks forever. Bound the accumulated response instead (as the other wire modules do).
    chunks, total = [], 0
    while True:
        (header,) = struct.unpack("<H", recvn(sock, 2))
        length, last = header >> 1, header & 1
        total += length
        if total > _MAX_MESSAGE_LENGTH:
            raise InterfaceError("backend message too large (%d bytes)" % total)
        chunks.append(recvn(sock, length))
        if last:
            break
    return b"".join(chunks).decode("utf-8", "replace")

def _putblock(sock, text):
    data = text.encode("utf-8")
    off = 0
    while True:
        chunk = data[off:off + _MAX_BLOCK]
        off += _MAX_BLOCK
        last = off >= len(data)
        try:
            sock.sendall(struct.pack("<H", (len(chunk) << 1) | (1 if last else 0)) + chunk)
        except (socket.error, OSError) as ex:
            raise connection_lost(ex)
        if last:
            break

View on GitHub (pinned to 0a35b20e39)

When it happens

Trigger: Thrown at extra/dbwire/monetdb.py:43 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/94c96f4d904fc158. Report an issue: GitHub.